Starting with a random encounter and then scattered around the various games, Final Fantasy has always had its hidden enemies. These same enemies are much more difficult than the rest of the encounters around them and they are often more difficult than the final story boss. Many of these hidden enemies have been named super bosses and they continue to be placed at key locations throughout their games. Creating unique challenges for those that seek them out.

It started with Warmech in Final Fantasy 1 and still hasn't stopped. Final Fantasy has created a legacy of frustrating and yet satisfying to beat bosses. While there are ways to instantly kill them such as with Yojimbo in Final Fantasy 10, such ways will be discounted. Here are some of Final Fantasy's 10 Most Powerful Hidden Bosses, Ranked.

10 The Dark Magus Sisters (Final Fantasy X)

Final Fantasy 10's international, PAL and HD remaster versions all came with additional super bosses that require a lot of effort to find and defeat. Each of the Dark Aeons come with their own unique challenge but the Dark Magus Sisters are perhaps the most difficult of them all when fought together. The three dark sisters can be found quite easily, simply travel to Mushroom Rock Road after acquiring the airship.

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The dark sisters can be easy or insanely difficult depending on what you do. If you fight all three of them at once, you're in for a world of agony. Their first attack right out of the gate is their Overdrive, Delta Attack. This attack does 99,999 damage and ignores auto-life which means you need to summon an Aeon to take the hit for you. The reason they're not considered as any more difficult than the following entries is because you can fight them separately. When done so, they're not too difficult.

9 Adamantoise (Final Fantasy XV)

Final Fantasy 15's Adamantoise is a massive boss that remains hidden for much of the game. The reason this gargantuan superboss is hidden is because it has become part of the landscape, specifically it is Longwythe Peak. Now you would expect that this huge superboss would lead to a fight of epic proportions, right? Well, kind of. Initially, the fight was supposed to last many real-time hours but in actuality, the fight can be beaten within an hour or so.

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Adamantoise isn't listed higher because so long as you pay attention, there's not a lot of risk involved. As with all superbosses, you need a certain amount of strength to tackle it. Once you have that strength, the Adamantoise is little more than one massive health bar to whittle down. Its attacks do decent damage but nothing you can't handle.

8 Omega Mark XII (Final Fantasy XII)

It's not difficult to stumble upon Omega Mark XII and when you do find it, its disguise as a giant treasure chest isn't convincing. What is difficult is being able to activate the fight. The requirements are simple, you need to have made it to the area before the Ultima boss fight and accepted the quest to hunt Yiazmat. The process to getting to Ultima is long but once you have done it, you can finally fight Omega Mark XII.

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The fight itself is both simple and potentially difficult. Omega Mark XII will always attack the nearest target and it will never target a party member who has been vanished. You can also use lure on your tankiest party member. With either of those things done, simply find a way to keep that one party member alive. Which isn't easy because this hidden boss does a lot of damage per attack and attacks fast.

7 Ruby Weapon (Final Fantasy VII)

Perhaps the most well known of all of these entries, Ruby Weapon is not too difficult to find. To access this difficult fight, you need to have defeated Ultimate Weapon and another random encounter. Hilariously, and adding to its hidden status, there have been reports of it staying invisible on the world map even after doing things properly. Though this is potentially due to player error.

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The fight itself is hard, arguably the toughest fight that Final Fantasy 7 can offer. Ruby is immune to anything you throw at it until its tentacles are exposed and in order for that to happen, only one party member must be left alive. There are numerous ways to overcome this problem and defeat Ruby weapon but that doesn't mean he doesn't deserve a place as one of Final Fantasy's most powerful hidden bosses. He has been around for a while after all.

6 Final Fantasy 8's Omega Weapon (Final Fantasy VIII)

Final Fantasy 8's Omega Weapon is up next and boy does it earn its place. To start, it's hidden within Ultimecia Castle, the final dungeon and it requires some work to get to the fight. Your party is split into two, you need to have one party stand in a particular place and use the other party to ring a bell. This activates a timer and you must use the first party to find Omega Weapon and fight it.

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Omega Weapon has a variety of attacks that either kill you or severely weaken you. The worst attacks are Megiddo Flame and Terra Break. Megiddo does 9998 damage to all party members and Terra Break does 16 hits of 4000 damage. Thankfully protect helps reduce Terra Breaks damage and Megiddo is followed up by a gravity attack, giving you ample time to limit break and heal. Omega Weapon is dangerous but ultimately predictable.

5 Vercingetorix (Final Fantasy XIII)

One of Final Fantasy 13's two superbosses and the final mark in the Cie'th stone missions. This Undying enemy is going to test your knowledge and ability to utilize the games mechanics. This superboss with a long and strange name is actually named after the King and Chieftain of the Arverni tribe, who tried and failed to revolt against Roman forces.

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As for the battle itself, it's one of those fun boss battles that gets harder as you damage the boss. At certain health thresholds, Vercingetorix sprouts more wings which in turn means more damage done to you and, when it casts its Impenetrable Aura, more buffs for it. The secret to overcoming this boss lies in using poison to whittle down its massive health pool and then turtling up at key moments.

4 Omega (Final Fantasy V)

Omega has been with the Final Fantasy series for a long time now, making appearances in one form or another in many of the games. Its first appearance was in Final Fantasy 5 and you could easily and happily be on your way to finishing the story without ever fighting it. Omega simply wandered around, letting you move past him if needed.

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If you did decide to fight him it was likely to be short affair. Short for you, that is, because Omega isn't a hidden superboss that you can fight without preparation. But there are ways to easily dispatch him and when the game was re-released later on, a newer and stronger version of him, Omega Mk. II appeared. However, both are susceptible to the Bards Romeo's Ballad, which inflicts stop.

3 Yiazmat (Final Fantasy XII)

Yiazmat is Final Fantasy 12's beefiest boss. This beasty is known for taking hours to defeat it and for its ability to grow more dangerous towards the end of the battle. In order to attempt the battle, you have to hunt most of the marks and defeat the optional boss, Hell Wyrm. Yiazmat is also the reason Montblanc created the guild as Yiazmat killed his mentor.

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To start, Yiazmant has over 50 million health points. To make things more difficult, he receives damage reduction once he's half dead, and an increase to his attack power around the 20% hp mark. Yiazmat can also inflict instant death with normal attacks. At the end of the long battle, though, Yiazmat is mostly about enduring it all as you can leave, heal and save as needed (though he can cast regen on himself). Still, Yiazmat deserves a place as one of the most powerful superbosses.

2 Ozma (Final Fantasy IX)

Here's another infamously difficult hidden boss, Ozma. Hailing from Final Fantasy 9, Ozma requires the player to complete the Chocobo Hot and Cold mini-game in order to reach him. Additionally, the Friendly Monsters side quest is advised as it allows him to be hit by physical attacks and weakens him to the shadow element. Once you've found him, it quickly becomes apparent why he's considered so difficult.

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Ozma can cast a variety of damaging attacks and status effects to hinder the party. What abilities he uses is dependent on whether the turn is an even one or an odd one. Additionally, Ozma's ATB gauge will fully fill up when the player targets him with any command. All of this combined with the somewhat random nature of Ozma makes him exceptionally difficult to defeat.

1 Penance (Final Fantasy X)

The ultimate superboss in a game full of them, Penance. When you defeat your last Dark Aeon this hidden boss will finally reveal himself. To fight him you must simply select him from the list of locations. Ignoring the use of Yojimbo's Zanmato, Penance is an absurdly difficult boss who you shouldn't fight until you've maxed out your stats.

With 12 million health, nearly maxed stats and elemental absorption, Penance shows no mercy. Its left and right arms allow him to cast his most powerful ability, Judgement Day. Penance's right arm can petrify and shatter one of your characters, permanently removing them from the battle. He is deserving of the number one spot on this list because of the sheer amount of preparation, determination and strategy needed to defeat him.

NEXT: Final Fantasy: The 10 Hardest Bosses In The Franchise, Ranked