Borderlands 3 players have likely already beaten the main game and moved on to endgame activities, Mayhem Mode, and True Vault Hunter Mode. One endgame activity that most players are looking forward to, though, is the Raid Boss, but this is despite the fact that Gearbox has maintained radio silence on any raid boss information. While it has yet to appear in-game, there has been quite a few data miners digging through the code in pursuit of said creature.
Before moving forward, it's worth highlighting that this information comes from data miners and could therefore be subject to error. Gearbox has announced no official information concerning the raid boss, but with the evidence piling up, it's hard to imagine what else this could be in Borderlands 3. This information also suggests that the boss is a ways off, so no one should take this to mean that it will be added anytime soon.
First off, the raid boss appears to be named Korilax the Invincible and is supposedly a large Varkid-like raid boss. This bit of information seems to be the most reliable, as it comes less from ambiguous coding and more from the game itself. Korilax the Invincible isn't a name BL3 players would be familiar with, but during the mission to find his prison buddies, Sir Hammerlock name drops the creature, stating it "owed [him] a favor." Past raid bosses have all been related to Sir Hammerlock in some way, so this makes sense as a tease of the creature's existence.
The idea that it is a giant Varkid comes from pre-release footage that shows players fighting, well, a giant Varkid. On top of that, the arena that Borderlands 3 players fight it in is the exact arena found in the game, located in Ascension Bluff. Players found a way to make it to the arena, without opening the Ascension Bluff door, and show off the area. This obviously didn't spawn the raid boss, but it did confirm the gameplay footage took place here. Furthermore, another player used a different exploit to find the lead-in room, which also appears to be where a ton of loot will spawn upon defeating Korilax the Invincible.
The evidence doesn't stop there, however. Data miners have found code in the game to confirm that there is a Varkid boss somewhere, though it's model and other coding was missing. Considering Sim Hammerlock's association, the location of the arena, and the fact that there isn't a Varkid boss of such scale elsewhere in the game, it seems safe to assume that Korilax the Invincibile is a giant Varkid that will spawn in Ascension Bluff.
Players have been trying to open the door in Ascension Bluff since the game launched, which just doesn't seem like a real possibility at this point. That said, based on other similar doors found in Borderlands 3, some think that there will eventually be a special mechanism to open or even that BL3's Ava would have to shoulder the responsibility. Gearbox just doesn't seem ready to reveal that quite yet.
Morever, since Korilax's code is missing, this means one of two things: Korilax isn't yet ready to fight, or Borderlands 3 is intentionally hiding the code for another reason. Either way, players still have to wait before they can tackle this fan-favorite endgame activity and potentially farm this Borderlands 3 boss for new legendary weapons and loot.
Borderlands 3 is out now for PC, PS4, and Xbox One.