Borderlands: The Pre-Sequel's second DLC expansion, the Ultimate Vault Hunter Upgrade Pack: The Holodome Onslaught, is set for a 16th December release on PS3, Xbox 360 and PC. This add-on is based around a challenge arena where players must team up to fight impending waves of enemies. Its story is that two vault hunters, Gaige and Axton, missed out on the events during the core game and want Athena to recount the story of what happened, but to pretty much keep it to the good parts. The violent parts.