Bugaboo is found by Jimenez and the Protagonist being tortured in one of the laboratories at Sector Bootes early on in the game. Further analysis of the demon reveals his physical makeup to be only about 75% demon, and though it is not stated directly, the remaining 25% is implied to be human, presumably one of the Elves' crewman. Jimenez befriends the demon and allows him to join his party.
Later on in the game, during the reconnaissance mission at Jack's Squad's HQ, Jimenez and Bugaboo are captured and subjected to cruel experimentation, leaving Bugaboo barely clinging to life. Jimenez asks the Protagonist to fuse them together using the Demon Fusion App, and regardless of the choice selected by the player, Jimenez will subsequently emerge in his Awakened form.
Bugaboo is available to the player in three different forms via use of the password system.