Weapons that are crafted by McCabe usually come with attached mods that cannot be taken off or replaced. Any weapon not crafted by McCabe has an open weapon mod slot for the various mods you find throughout the game. These crafted weapons are special guns that you have to acquire from defeating bosses.
The mod powers are themed and relate to the boss or world it came from in some way shape or form. The later in the game you get the mod, the more creative the mod gets in battle. You can teleport enemies to different realms or unleash hellfire and burn them in groups. Weapons with attached mods in Remnant: From The Ashes can be hindering to use if you've favored two mods you would normally apply to your guns. They are usually used for special moments where you need to think on your feet.
10 Defiler - The Harrow
The Harrow is a boss found in Rhom. If you kill him the normal way, you'll receive materials to craft the Defiler. This is a smaller, secondary weapon that acts as a mini-shotgun. It fires heavy and strong, applying radiation damage with its attached mod. The mod unleashes six bouncing, radioactive balls that will ricochet off of walls. Less useful in open spaces, better to use if you're somewhat cornered and there's a lot for the projectiles to bounce off of.
9 Hive Cannon - Ixillis
The Hive Cannon hand gun is crafted from the materials you get from defeating Ixillis. Ixillis is one of the hardest non-optional bosses, found in Corsus. This is only if you don't kill them the alternative way. This gun shoots large and powerful impacts that knock back teammates and enemies alike. The attached mod unleashes a stronger version of this impact that showers the enemy with insects and deals corrosive damage.
8 Spitfire - Singe
If you've been wanting a flamethrower, look no further. The Spitfire acts as a submachine gun, shooting at a rapid pace that will mow down small enemies with ease. It's a secondary weapon that does fire damage. The attached weapon mod is a flamethrower. That's it. You press the mod button and everything goes up in flames.
The materials for this gun are acquired by defeating Singe, the fire breathing dragon found on Earth. Singe is a randomized encounter that you may need to reroll your campaign to find and he too has an alternative loot drop that will reward a different weapon than the Spitfire.
7 Curse Of The Jungle God - The Ravager
The Curse Of The Jungle God, a long word for a hand gun, is of Yaesha decent. The materials for this gun are received after defeating the large wolf-like boss on Yaesha. The Ravager is a randomized encounter that you may have to reroll your campaign to find.
The Ravager has an alternative loot drop that will not grant you the Curse Of The Jungle God. This gun will shoot bursts of shock-filled energy at your target. The weapon mod allows you to aim and project a large tentacle that will sprout out of the ground. This tentacle is stationary and will whip and attack any enemy that walks by it, dealing shock damage.
6 Ruin - Undying King
Ruin is an assault rifle with a scope, obtained by defeating the Undying King in Rhom. It shoots fast and you're able to attack from afar and up close. The real prize from this weapon isn't the damage or its value in a fight, but rather the mod. The attached weapon mod brings you back to life.
Not only can you save and utilize your dragon hearts, but you're granted another life with this mod. When the mod is charged up, if you go down injured, you just get back up. No need for hearts or a revive. If you use the Cultist armor set to recharge your mods fast, you'll never have to waste a dragon heart again.
5 Eye Of The Storm - Totem Father
Eye Of The Storm is a long gun, main weapon that projects shock-filled energy towards your enemies. It's acquired by defeating the Totem Father found on Yaesha. He's a randomized boss you may have to reroll to find. The attached weapon mod for this gun fires an even larger orb of shock damage. Because of the shock damage, enemies will have the overloaded effect that will allow them to explode and take other enemies down with them.
4 Devastator - Unclean One
The Unclean One is a randomized Corsus boss that once defeated, will grant you the materials to craft the Devastator. The Unclean one has an alternate loot drop that will not give you the Devastator. This is the heaviest crossbow in the game, releasing five large bolts towards your enemies. The other crossbows only release one, normal sized bolt.
If you thought five large bolts was overkill, think again. The attached weapon mod is all of those bolts combined into one ginormous, single bolt. This bolt deals 125 damage, staggers enemies, and causes bleeding which does even more damage over time.
3 Particle Accelerator - Claviger
This is the strangest and most interesting looking long gun in the game. Reloading it makes the entire gun un-peel itself and spin in the air. It's materials are received from defeating Claviger, a randomized boss found on Rhom. This weapon is an alternative loot drop. You must not allow him to absorb any adds during the entirety of the fight.
Much like the Hive Cannon, its attached mod can be annoying to other teammates. It produces a large, gaping hole of gravity that sucks in anything nearby. When a lot of enemies are inside, it explodes and deals even more damage. Make sure no friends are within melee distance before use.
2 Repulsor - The Dreamer
This is an end game weapon. Spoilers ahead. The Repulsor's materials are received after defeating The Dreamer in Ward 17. It acts like a shotgun, dealing 100 base damage with multiple bullets in one go. The attached weapon mod essentially teleports your enemies to another dimension for a short amount of time. Much like The Dreamer boss fight, when they come back they are susceptible to extra damage for a while before reverting back to normal.
1 Sporebloom - The Ent
The Ent is a randomized boss found on Earth. He's part of your beginning journey in Remnant From The Ashes and if killed the normal way, you'll receive materials for the Sporebloom shotgun. It's a close-counters weapon that deals rot damage both with and without mod usage. The attached mod will project an explosion that leaves behind a cloud of rot.