The trials in Sea of Thieves Season One are designed to introduce and highlight specific aspects of the game to new and experienced players that might have so far ignored some elements of the game. The Combat trials are based around combat, unsurprisingly, but also the Reaper’s Bones, the newest Trading Company on the sea, with a desire to see players fight each other for mysterious purposes, as well as financial gain.
There are seven Infamous Trials of Combat, each made up of several deeds that ask you to complete a specific objective, or series of objectives. This guide will take you step by step through each trial and deed for anyone familiar or unfamiliar with the game since the introduction of the first Season.
How To Complete The Infamous Reaper Trial In Sea Of Thieves
- Hand in a broken Emissary Flag as a Reaper’s Bones Emissary
- Purchase and equip the Reaper’s Bones Costume as a Reaper’s Bones Emissary
- Hit a ship with a firebomb fired from a cannon
- Reach Grade 3 as a Reaper’s Bones Emissary
The Infamous Reaper tasks want you to get more acquainted with the Reaper’s Bones, after introducing you to them in the Ambitious Reaper challenges. The first deed wants you to hand in a broken Emissary Flag as a Reaper’s Bones Emissary. So, the first thing you’ll need to do is make sure that you are a Reaper’s Bones Emissary. To become an Emissary you have to buy an Emissary flag and raise it on your ship. You can buy the flags from any outposts, for 20,000 gold, with each Trading Company having their own table dedicated to the purchase and rising of the flag. They’re not exactly cheap for new players, but you’ll own the flag permanently once you’ve bought it.
Reaper’s Bones Emissary Flags can be purchased from the Servant of the Flame at Reaper’s Hideout at I/J-12 and equipped by voting on their Emissary Table on any outpost, but these are often hidden out of sight. Listen out for the sound of skeleton that is normally tied to the table to give you a clue as to where it is. Remember that Emissary Flags aren’t flown from the Flag Box in the Crow’s Nest and must be equipped from the Emissary Flag table on the outpost.
Once you’ve bought and equipped the Reaper’s Bones Emissary flag, you’ll have to find and turn in a broken Emissary Flag to complete this deed. Unlike all other treasures in Sea of Thieves, the broken Emissary Flag can only be found in one way: sinking another player ship that is flying an Emissary Flag found on the sea. Once a player ship is sunk with an Emissary Flag equipped, you’ll be able to find the broken flag floating with the other loot where the ship sank.
Once you’ve got the flag, head to the Reaper’s Hideout and turn it into the Servant of the Flame to complete the deed.
Sinking other players can be difficult, as they’re often smarter than the skeleton ships and much, much more violent. Use Cursed Cannonballs to take an early advantage and try and hit them as much as possible below the waterline. Gunpowder Barrel mines can be extremely effective if you can get one under the hull. Once they’re taking on water, you’ll want a boarding party to fire themselves onto their ship to try and prevent them from bailing and repairing. This can also be a useful trick if they’re proving a hard target to hit.
Also look out for ships left anchored while the crew is onshore, as you might be able to sink them, grab the flag, and get away before anyone can react.
Remember though that other players might try and board you and use every trick you’re using against you. If you want to practice your naval combat, try playing a few rounds of the Arena mode to get a feel for it.
The second deed asks you to purchase and the Reaper’s Bones costume as a Reaper’s Bones Emissary. Once again that means you’ll have to make sure your flying the Reaper’s Bones Emissary Flag from your ship to unlock this deed. You have to buy it from Reaper’s Outpost but from there is can be equipped from their table on any outpost. Once you’ve equipped that from the table at any outpost, you’ll have to wear the Reaper’s Bones costume too.
To buy the costume, you’ll have to have already bought the Reaper’s Bones Emissary Flag for 20,000 gold from the Servant of the Flame. Once you’ve done that you can see that the slot you bought the flag from now sellers the Reaper’s Bones Costume. It's not cheap, at 68,300 gold but once you’ve bought it and equipped it, the deed will unlock as long as you’re flying the Reaper’s Bones Emissary flag as well.
The third task demands that you hit another ship with a firebomb launched from your cannon. Each time your ship spawns you’ll find a few firebombs in your cannonball barrels and you can also find them in barrels scattered through the world.
Load at least one your the cannons on your ship with a firebomb, and then look for a target. The easiest way to complete this deed is to look for a skeleton ship. When engaged in combat these ships maintain their range and are a much easier target than the unpredictable players. To use the firebomb properly, you want to try and hit the deck of the ship to disrupt the crew's movements, but to complete this deed all you have to do is hit the ship with one of the bombs.
If you’re working with a crew though, each one of you will have to land a hit to get the deed.
The final deed in the Infamous Reaper Trial is to reach Grade 3 as a Reaper’s Bones Emissary. Emissary grades are earned while flying the Emissary flag so make sure your crew has voted to hoist the Reaper’s Bones Emissary Flag before you start this journey.
Once flying, you’ll improve your Emissary grade by doing things for that Emissary. Generally speaking, you can do it for completing voyages as well as defeating Skeleton Ships, Megalodons, and Krakens. The Reaper’s Bones Grade is improved most speedily by sinking other player ships that are flying Emissary Flags themselves. Players without an Emissary Flag don’t offer any experience and are best to be avoided. For each grade improvement you unlock, the rewards handed into that Trading Company will be boosted.
Most importantly, your Emissary grade will be reset if your ship is sunk, or if you quit the game. So its incredibly important to keep your ship afloat as you hunt down others. This is much easier to do with a crew of at least three so that one can steer, another can shoot, and the final one can repair, bail, and generally keep the ship on top of the water.
There are five Emissary Grades in total, but you only have to reach Grade 3 to complete this deed.
How To Complete The Infamous Mercenary Trial In Sea Of Thieves
- Destroy Skeleton Captains
- Hand in Villainous Bounty Skulls to the Order of Souls or the Reaper’s Bones
- Destroy an Ashen Guardian
The Infamous Mercenary Trial of Combat focuses on the Order of Souls Trading Company and the voyages they offer. The first deed wants you to defeat ten Skeleton Captains. While Captains can be found randomly across the Sea of Thieves, they are most easily hunted on an Order of Souls Bounty Voyage that instructs you to head to a certain island where up to four Skeleton Captains can be found.
Once you’ve made it to the island, you’ll have to find their crew, noted by the outfit variant skeletons and the change in music. Once you’ve defeated a few rounds of the crew, the music will change again and the Captains will reveal themselves. Defeat ten of those Captains to complete the deed.
The second deed wants you to hand in three Villainous Bounty Skulls to either the Order of Souls or the Reaper’s Bones. Every Skeleton Captain defeated will drop their Bounty Skull that comes in four basic variants. Villainous Bounty Skulls are the rarest and most valuable of the most four and easily stands out thanks to the floating skull fragments and eerie green light.
These skulls can also be rewarded for other tasks as well such as defeating a Skeleton Ship, and sometimes simply found onshore. While they are the most valuable, they are not uncommon, and once you have three you can hand them in to the Order of Souls on any outpost or at the Reaper’s Hideout at I/J-12.
The final deed of the Infamous Mercenary Trial wants you to destroy an Ashen Guardian. These are rare Skeleton Captains that spawn randomly through the game, and cannot be found through a Bounty Voyage. These fiery-looking Captains protect Orders that can be used to find Ashen Chests, but you don’t need them to complete this deed.
Keep an eye on any islands you sail past from any skeletons that might be glowing a faint red, and be ready to drop anchor and leap to action. They can also spawn during some waves of an active Skeleton Fort, so if you’re struggling to find any on islands, keep an out for the Skull Clouds that indicate an active fort.
How To Complete The Defiant Reaper Trial In Sea Of Thieves
- Hand in broken Reaper’s Bones Emissary Flags as a Reaper’s Bones Emissary
- Hand in a Reaper’s Chest
- Hand in a Reaper’s Bounty Chest
Whereas the Infamous Reaper Trial wanted you to become the most terrifying pirate hunter on the seas, the Defiant Reaper wants you to hunt the hunters. The first deed in this trial wants you to hand in a broken Reaper’s Bones Emissary Flag as a Reaper’s Bones Emissary. First, you’ll have to fly the Reaper’s Bones Emissary flag from your ship (and information on how to do that can be found in the Infamous Reaper section of this guide).
Once you’ve done that you’ll have to find and sink another player ship that is also hoisting the Reaper’s Bones Emissary Flag. These players are probably battle-hardened pirate hunters and are likely to challenging naval warriors, but they can also be difficult to find. You can simply make sure you’ve got the Reaper’s Bones Emissary Flag on your ship each time you play and hope you find them, but if you’re looking to get this out the way, the best option is to patrol the waters around Reaper’s Hideout at I/J-12. This is where the Reaper’s Emissaries will have to return their broken flags and so you should be able to attempt to intercept them en route and engage in battle.
If you’re lying-in ambush, you can also try and set a trap if you have a big enough crew. The easiest way to do this is to gather a few Gunpowder Barrels and hide them around the coast of the Reaper’s Hideout, swimming out with one once you spot the Emissary Flag coming in and try and detonate it under their ship before beginning a full-blown assault.
There is one final option for anyone that is really struggling though. If you cannot find or defeat a Reaper’s Emissary, you can also turn in your own broken flag. Though you’ll get next to no reward for it. If you destroy your own ship and hand in the broken flag you had equipped, you will complete this deed.
The second deed is to hand in a Reaper’s Chest. As mentioned in the Ambitious Reaper Trial Guide, these are special chests that are most commonly found in Shipwrecks scattered across the Sea of Thieves. You can spot if any have spotted by looking on the horizon for spiralling red and green lights that appear above the chest before it has been handled by a player.
You can also see Reaper’s Chest icons on the map on your ship. They look like a red skull with a red circle around them. If you can’t find any in Shipwrecks look on the map for any that might have been moved. If the icons are moving, that means another crew is traveling with it. Its up to you whether you want to engage with that ship and try and claim their prize.
And remember when you have one on your ship that every other player can see you on their map under the same icon. That makes you a potential target so be careful on any ships that attempt to pursue you from behind or ambush you ahead. For new information check out the Ambitious Reaper Trial Guide.
The final deed wants you to retrieve a Reaper’s Bounty Chest. These are the rarer and more valuable variants of the Reaper’s Chest, but follow the same basic principles. They can be found in Shipwrecks primarily, but the spirals above them will be yellowy rather than red and green. The icon that appears on the map will be a white skull with a gold coin, surrounded by a gold circle.
Because these are a lot more valuable, they are more sought after and players are much more likely to attempt to intercept a ship carrying one if they are in range. Since the chest can only be handed into the Servant of the Flame at Reaper’s Hideout you might also expect an ambush if it looks like your ship is handing there. Try sailing to other islands and attempting to lure ships away from Reaper’s Hideout if you see any lurking there. Since the chest makes your ships visible, you won’t be able to hide, so you’ll have to fight, or run.
Once you turn in the Reaper’s Bounty Chest, you’ll have this deed completed, and be rewarded 10,000 gold for your trouble.
How To Complete The Infamous Ghost Hunter Trial In Sea Of Thieves
- Complete a Ghost Ship Voyage for the Order of Souls
- Hand in Skulls of the Damned
- Defeat Flameheart’s flagship, the Burning Blade
While skeletons might be the main foe you’ll face in Sea of Thieves, ghosts can rear their ugly heads too and the Infamous Ghost Hunter wants you to face them. The first deed in Infamous Ghost Hunter wants you to complete a Ghost Ship Voyage. Unlike the Bounty Voyages that lead crews to Skeleton Crews, Ghost Ship Voyages direct your crew to an island surrounded by Ghost Ships. Players will have to battle a fleet of these ghost vessels before a Ghost Captain Ship will appear. Once the Ghost Captain Ship is defeated which you can identify from its undead unicorn sails, the other ships will depart and the voyage will be complete.
As mentioned, this voyage is offered by the Order of Souls Trading Company so you can look to purchase one from any of their representatives at any Outpost. If there isn’t one available to buy you’ll have to get another crewmate to see if they can get on, or head to another outpost.
Ghost Ships operate differently from skeleton ships and so your approach and tactics will also have to change. Most notably a defeated Ghost Ship doesn’t sink but instead explodes with energy, knocking all ships in range around. This can change your course as well as that of other ships so try and keep your distance. But because Ghost Ships don’t sink, you don’t have to aim for the waterline to be the most effective with your cannons. Instead, you can aim for any part of the Ghost Ship and it will do the same damage. In fact, Ghost Ships can be reliably defeated in three direct cannonball strikes.
Because of the relatively few cannonballs it takes to defeat, it is recommended that you don’t use firebombs or any cursed cannonballs and instead focus on committing as much regular damage as possible.
Ghost Ships also use ghostly munitions you’ll have to be aware of. While the regular ghostly cannonballs act exactly like their more physical counterparts, there are Flame Phantom and Wraith Cannonballs are to handle as well. Flame Phantom Cannonballs appear as red spirits while arching through the air. On contact they erupt in fire exactly like firebombs so make sure you’ve got your water barrel filled on your ship to douse any flames. Wraith Cannonballs are the most dangerous ammunition that can be fired towards you, and appear as screaming green ghosts when fired. Upon contact the Wraith Cannonball will deal a lot of damage to the ship and shunt it as if it hit by an explosion. Although it's very difficult to avoid one racing towards you, players and crews should be prepared to repair and readjust their ship when they see or hear one coming.
Finally, these voyages should be not be attempted alone. This naval battle will require a crew to steer, shoot, and repair and at least two pirates should be needed to handle all the jobs at once.
The second deed wants you to hand in ten Skulls of the Damned. These unique skulls are harvested from the ghostly crews of Ghost Ships. Since Ghost Ships only spawn in Ghost Ship Voyages or when fighting Captain Flameheart, you’ll have to take on the voyage, or look out for his floating, mocking face in the sky.
It can be tricky to collect the Skulls of the Damned during the battle with all the ghosts trying to kill you and everything. If you have a four-person crew one player might be able to jump overboard and grab a Skull floating in the sea and get it back aboard. Otherwise, try and note where the Ghost Ships you defeated were in relation to the island so that you can swing back when the fight is over, or when you get a moment between attacks.
Once collected you can hand in Skulls of the Damned to any representative of the Order of Souls or the Servant of the Flame at Reaper’s Hideout.
The final deed in this trial expects you to defeat Captain Flameheart’s flagship, The Burning Blade. While it is a Ghost Ship battle, his ship will not spawn during a Ghost Ship Voyage. Instead, look out for his giant orange face that appears in the sky periodically. Head towards it and once in range, Ghost Ships will spawn.
Much like the Ghost Ship Voyages, they will come in several waves before his flagship appears. Several waves will patrol around the ship and you’ll have to chase them or sail counterwise to their movement to attack them.
Be on the lookout for the ghostly cannonballs mentioned above and make sure you’ve got a three-person crew or higher before attempting this task. It will also be a much bigger battle than the typical Ghost Ship Voyage so you’ll have to make sure you’re stocked up on cannonballs and wooden boards to survive the extended encounter.
Once his flagship, which you can identify by its sails that look like a flaming heart, is defeated, you will have completed the deed. Unlike the regular Ghost Ships, the Burning Blade and the larger ships that protect it will take more direct hits than their smaller counterparts, but they still explode when destroyed.
How To Complete The Infamous Warsmith Trial In Sea Of Thieves
- Rock another crew’s ship using the Wraith Cannonball
- Hit a ship with different types of purple Cursed Cannonball, while flying the Reaper’s Mark flag
- Read Wanda’s Journal on Thieves’ Haven
The Infamous Warsmith trial is about that noblest of pastime: firing cannons. The first deed of the Infamous Warsmith Trial wants you to rock another ship using the Wraith Cannonball. As mentioned in the Ghost Hunter section, the Wraith Cannonball is the most powerful weapon used by the Ghost Ships, dealing impressive damage and violently moving all ships in range when it detonates.
Unlike any other Cursed Cannonballs you might have come across, the Ghost Ship ammo cannot be found in any normal barrels in the game. Instead, they can only be found in a Cannonball Crate of the Damned, a resource crate dropped by defeated Ghost Ships. That means you get this deed you will have to go on a Ghost Ship Voyage or battle Flameheart’s fleet, although you don’t have to finish either.
Watch the water where the ships disappear all look for any resource boxes that might be floating on the waves. You might have to drop the anchor in order to jump out and grab the supplies, or you can attempt to use the harpoon gun.
Once you’ve got a Cannonball Crate of the Damned onboard, check you’ve got a few Wraith balls, so you can have more than one chance to hit. The wording of the deed is a bit confusing but you will have to hit another player ship to complete this deed. A skeleton ship will not count so look for the full sails of a player ship and set course.
Oddly enough the players in question will probably attempt to retaliate when fired upon, so be ready for a fight, but once a Wraith Cannonball hits their ship, the deed will complete.
The second deed wants you to hit a ship with three different purple Cursed Cannonballs all while flying the Reaper’s Mark. The Reaper’s Mark is not the Reaper’s Bones Emissary Flag, and is instead one you can fly from the Crow’s Nest. But be warned, the Reaper’s Mark will place you on every map in the server, so every other crew can see exactly where you are as well as your heading.
This means that the only player ships you’ll be likely enough to get close to will be looking for a fight, or paying no attention but you shouldn’t make that assumption. Look out for signs of ambushes like Alliance Flags waving at the top of their Crow’s Nest and sea rocks that might be hiding other ships. Other players and Gunpowder Barrels might also be in the water, so be on the lookout for any traps as well. You don’t need to win the fight to complete this deed, but you do need to survive long enough to fire the shots.
It is recommended that you instead try and complete this deed on Skeleton Ships rather than players, but once the Reaper’s Mark is up you might gain unwanted attention.
Cursed Cannonballs are the special cannonballs found in barrels around the world that have a special effect when they strike and come in two colours: green and purple. If you’re looking to do this deed, you should scour the starting outpost for as many of these Cursed Cannonballs as possible so you’ll have plenty of opportunities. That being said, you don’t need to hit the same ship three times to complete the deed and you can spread it out over as many sessions and encounters as necessary.
Purple Cursed Cannonballs always affect the ship they hit, and these are the ones that you’ll need to complete this deed. There are six types of Purple Cursed Cannonballs.
The Anchorball will drop a ship's anchor on impact stopping the ship dead in the water.
The Ballastball is perhaps the most dangerous Cursed Cannonball available, as they lower the ship they hit further under the waves. That means that any unrepaired holes that are made above the waterline will start taking on water and can almost immediately sink a ship.
The Barrelball will seal off all the barrels of the ship they hit for several seconds, which means that crews will only have access to what is in their inventory, which can be effective if timed correctly.
The Helmball similarly prevents a crew from using the steering wheel of the ship, leaving them on whatever heading they were on when it struck.
The Peaceball remove a ships ability to use their cannons for several seconds, incredibly useful if you can use it before sailing on their broadside.
The Riggingball will raise the sails of the ship and prevent them from being unfurled for several seconds, greatly affecting their speed.
Once you’ve collected several of these Cursed Cannonballs, and made sure the Reaper’s Mark is flying above your ship you’ll be ready to find another vessel and blast it to complete the deed. Cursed Cannonballs fire at the same trajectory as regular cannonballs so you can use them to gauge your aim if you’re worried about missing too many. If you’re struggling to find any Skeleton Ships consider looking for a Ghost Ship Voyage from the Order of Souls.
The final deed wants you to find Wanda’s Journal on Thieves’ Haven. Thieves’ Haven is one of the largest islands in the game and can be found in the Ancient Isles at L/M-20. While the island is huge, Wanda’s journal can be found very easily and doesn’t need you to explore its many caves and tiers.
Instead, put down your anchor on the northeastern beach and look for an unlit bonfire and a half-buried skeleton. Wanda’s Journal should be beside them on the sand. As to why this journal is listed amongst other deeds regarding the Cursed Cannonballs, you’ll have to read it to find out.
How To Complete The Infamous Detonator Trial In Sea Of Thieves
- Explode Gunpowder Skeletons in a chain reaction
- Take out a group of 3 skeletons using a Gunpowder Skeleton
- Kill a shark using a Gunpowder Barrel
The Infamous Detonator Trial wants you to utilise the awesome, and often chaotic power, or the Gunpowder Barrels you can find scattered over the Sea of Thieves. The first deed wants you to create a chain reaction of exploding Gunpowder Skeletons. Gunpowder Skeletons are the skeletons that carry large gunpowder barrels and attempt to blow themselves and you up when you get too close. They can be any variant of skeleton and might appear whenever a skeleton wave spawns.
Because this deed needs you to start a chain reaction of at least two, the opportunity to complete this is more luck than skill. Order of Souls Bounty Voyages will give you more chances at fighting spawning waves of skeletons, and active forts will give you bigger waves to fight and thus improve your odds further.
Once you have at least two Gunpowder Skeletons spawn at the same time, you’ll have to make sure they are standing reasonably close together then use a preferably ranged weapon to shoot and detonate one barrel, with the explosion triggering the second. Once both barrels have exploded, the deed should complete.
The second deed in the Infamous Detonator Trial wants you to take out a group of at least three skeletons with a Gunpowder Skeleton. This is easier than the first deed as you only need to find a single Gunpowder Skeleton to achieve it. Once again though, you’ll find the biggest collection of skeletons on active forts or Bounty Voyages.
The best trick to ensure the explosion will destroy at least three skeletons is to make sure they are as tightly grouped around the barrel as possible. To do this you can either circle the entire group so they begin to curve and follow the same path, or if they are too far apart you can weave between them so they will get closer together. Remember that a Gunpowder Skeleton will light the fuse when you get too close, and will only stop it if you get outside of range so be ready to sprint if you hear the fizzle.
Another important note is to make sure all the skeletons are vulnerable. It is not recommended that you attempt to do this on the Fort of the Damned as you’ll have enough to think about, but Shadow Skeletons will still pose a potential challenge. If you are attempting this against a hoard of Shadow Skeletons make sure you are doing so in daylight so that they won’t be immune to the damage.
The final deed in the Infamous Detonator wants you to kill a shark with a Gunpowder Barrel. This is a deed that has come up before in the Novice Bilge Rat Trial. To complete this deed you will have to use a Gunpowder Barrel to kill a shark at sea, but for more information, check out the relevant guide.
How To Complete The Infamous Firestarter Trial In Sea Of Thieves
- Burn a group of 3 skeletons at the same time
- Burn Skeletons using an Ashen Winds Skull
- Hit a ship with a firebomb fired from a cannon
Unsurprisingly, the Infamous Firestarter Trial wants you to use fire in combat. The first deed needs you to burn a group of three or more skeletons at the same time. The easiest and most effective way to do this is with the firebomb. Grab a few from your ship's cannonball barrel or from random barrels in the game and head to any island where skeleton can spawn. If you’re struggling to find a wave, try starting a Bounty Voyage or active fort. The type of skeleton doesn’t matter, so they can be anything from regular to golden, but if they are shadow make sure they’re vulnerable when you strike.
Once you’ve got your skeletons, you’ll need to make sure they’re grouped together, which is easiest with the sword wielding ones as they will pursue you relentlessly. Either circle or weave between them until they are tightly packed then simply throw a firebomb into the centre to ignite them all simultaneously.
The range of these blasts is further than you might expect so you’ll want to stan back to avoid being caught in the blaze, but as soon as they’re all on fire, the deed should complete. Its always good to remember that firebombs can be hand thrown as well as fired, so bare this in mind when you’re in naval combat and boarding an enemy vessel.
The second deed wants you to burn fifty skeletons using an Ashen Winds Skull. This is an incredibly rare skulls found by defeating an Ashen Lord. Ashen Lords are world events marked by a tornado of fire and ash that can be seen across the Sea of Thieves when one is active. Head to the island underneath the whirlwind and an Ashen Lord will spring up to fight you.
Ashen Lords are some of the strongest enemies in the game, with hugely damaging attacks and an incredibly large health pool. You shouldn’t think about facing one without a full crew and a lot of fruit to keep you in the fight.
When attempting to defeat an Ashen Lord there are a lot of things to remember, but the most important is to keep the ship at a safe distance. You might want to use the cannons to blast the Lord from a distance, but the Ashen Lord has several attacks that reach and damage a ship so it is better to keep it safe so you have somewhere you to spawn and somewhere to take the booty once you’ve won. Secondly, don’t use Gunpowder Barrels on Ashen Lords. While certainly effective are defeating enemies, The Ashen Lord has many area of effect attacks that will detonate most barrels at a distance, killing you and leaving themselves mostly unharmed. Ashen Lords can also boil the coastline like volcano eruptions in The Devil’s Roar so be careful around the water while you’re fighting.
Finally, like other stronger enemies in Sea of Thieves, Ashen Lords can summon an endless supply of grunts to fight alongside them. Look out for these extra enemies as they can quickly overwhelm you and cut off your retreat.
When you finally defeat an Ashen Lord, they will drop a lot of treasure but chief amongst it the Ashen Winds Skull. Like every other skull in the game, they can be turned into the Order of Souls or Reaper’s Bones for more reputation and gold. But unlike every other skull in the game, they can also be used as a weapon. When holding an Ashen Wind Skull, you can shoot flames forward, setting all flammable things on fire which is includes players and your own ship so be careful.
Each Ashen Skull will only be effective for so long though, and after the crystals visible while holding it stop glowing, it will become useless as a weapon. The total amount of fire breath a skull has is somewhere between thirty seconds and one minute. So after acquiring the skull, you’ll have to find a large hoard of skeletons, probably by sailing to an active fort or taking a Bounty Voyage from the Order of Souls, and using the skull to set as many alight as possible. You don’t have to destroy them with the Ashen Skull, simply setting them alight with be enough to count towards the deed. And you don’t have to burn fifty skeletons with the same Ashen Skull either so this can be done over several attempts. Once fifty have been scorched, the deed will be complete.
The final deed in the Infamous Firestarter Trial demands that you hit a ship with a firebomb fired from a cannon. This is exactly the same the Infamous Reaper deed at the beginning of this guide, so if you’re still unsure of the mechanics scroll on up and check it out.