True Vault Hunter Mode not real enough for you? Well, there's a cure for that. (And when that gets too easy, there's a cure for that too.) Ultimate Vault Hunter Mode is included in the Game of the Year Edition and was released as a patch for owners of the original version. (The patch allows anyone to play the higher difficulty mode for free, but players who don't own the Season Pass or Game of the Year Edition must purchase the Ultimate Vault Hunter Upgrade Pack 1 to get access to perks like the increased level cap.)
The Ultimate Vault Hunter Mode is intended for characters who have hit the previous level cap of 50, and those characters must first have completed all of the Story Missions in True Vault Hunter Mode. If you meet the conditions, you can set it as your playthrough mode in the game's Main Menu. It can be replayed infinitely; a new Main Menu option will allow you to reset your mission progress whenever you want to give it another go.
Unlike the True Vault Hunter Mode, which primarily provided a difficulty boost, Ultimate Vault Hunter Mode also adds new rewards and tweaks some of the game's stats to strengthen some of the strategies available to players.
Level Cap Increase. The Ultimate Vault Hunter Upgrade Pack raises the level cap from 50 to 61, allowing for more powerful character builds that borrow heavily from secondary skill trees. Note, however, that you still end up one level short of the amount you would need to get tier-6 skills from two different skill trees.
Tougher Foes. Not only will the foes you face rise to match your newly boosted levels, but a general health multiplier makes them about four times as resilient as they were in the game's normal difficulty mode. They're also now able to gradually regenerate health, so it's even more important to focus your attacks on eliminating individual foes rapidly. Fortunately, your foes will drop more ammo to compensate, and upgrades to the slag mechanic (see the note below) will allow you to boost your damage potential. Despite their increased strength, you only gain XP at 2/3 the normal rate in Ultimate Vault Hunter Mode.
Pearlescent Loot. Ultimate Vault Hunter Mode is the only game mode in which you can find Pearlescent weapons—the game's rarest tier of items. Pearlescent weapons can be found in chests and other loot sources, and are occasionally dropped by Legendary Loot Midgets (a new version of Loot Midget found only in this mode). They can also be dropped by other foes, although the odds are infinitesimally low. It's also possible to acquire them from the slot machines in Tiny Tina's Assault on Dragon Keep.
More Legendaries. Besides the new Pearlescent Loot, orange and other high-quality loot drops at higher rates than they did in the lower difficulty. The chances of getting legendary or unique items from bosses is also much higher. Combo relics also drop from Legendary Loot Midgets, as well.
Increased Capacity. The Black Market now sells additional tiers of upgrades, allowing you to increase your storage capacity by up to six new inventory slots and four new bank slots. There's also one additional tier of ammo storage for each weapon type. These upgrades are expensive, so the game now allows you to hold up to 500 pieces of Eridium at once.
Skip the Tutorials. Playthroughs in Ultimate Vault Hunter Mode begin at the Southern Shelf, with the "Cleaning up the Berg" mission, cutting out the introductory sections of the game.