After Montgomery Jakobs spent most of his ship-building budget on the Maliwan combat AI GenIVIV, he resorted to purchase a budget Tediore navigation AI to save his remaining funds, naming the AI "BALEX" due to Monty being unable to decide between the names "Alex" and "Barry". Both GenIVIV and BALEX soon took a liking to each other and started a relationship, but soon soured thanks to their frequently clashing personalities. As BALEX puts it later, their manufacturer differences prevented them from getting along. Their acrimonious parting of ways came when BALEX crashed the ship on the surface of Eden-6. GenIVIV ejected BALEX and inserted him into a teddy bear plush before leaving him to the mercies of the local fauna.
BALEX first appears during The Family Jewel as an unknown user attempting to call for help and the Vault Hunters save him after killing the saurian that ingested him. After revealing their allegiance to Wainwright Jakobs, BALEX agrees to help the them in retrieving the Vault Key fragment. With his knowledge of the ship, he walks them through GenIVIV's defenses and occasionally assists in direct combat whenever he is capable, despite GenIVIV's impediments including destroying the physical robotic bodies he is operating. When GenIVIV surrounds herself with an impenetrable shield, BALEX disables it, allowing the Vault Hunters to destroy GenIVIV's body and retrieve the Vault Key Fragment. They then take BALEX with them back to Sanctuary III.
After returning to the ship, GenIVIV hacks the systems, driving Sanctuary III into an asteroid field, damaging the windshield in the process. BALEX has the Vault Hunters install him into the ship. He kicks GenIVIV into a hard drive and restores the ship. He remains aboard serving his original purpose and will occasionally broadcast announcements through the PA system.
- Once installed on Sanctuary III, BALEX will occasionally give comments while on board the ship and during certain missions. He will always tell the character not to touch the ship's engine while passing it.
- BALEX will usually ask the character to go to the ship's bridge to squeeze him. His dialogue appears to be bugged, as he will always repeat that he shoved GenIVIV into a hard drive after his initial dialogue ends (mission dialogue during The Family Jewel).
- BALEX is the first character in the Borderlands franchise to use an uncensored version of the word "Fuck". He does so when warning the Vault Hunters about a saurian approaching (the quote in part is "...a fucking dinosaur..."). In previous uses of the word, it is censored as "F**k" or "F*ck"
- However, the "fuck" he says at the end of the story is censored for unknown reasons.
- The plush that contains BALEX uses the same model as the plush bear found during Childhood's End. Tannis mentions that it is based off a "Thracian Tetrabear", a species of bear with toxic claws.
- When BALEX appears as a mission item, picking him up will produce a light rubber ducky sound.
- BALEX never leaves the plush he was installed in, so his appearance prior to the events of the story is unknown. His ECHO image is also the plush bear he resides in.
- Unlike GenIVIV, BALEX is never seen projecting physical manifestation of himself.