4-LOM is a bounty hunter protocol droid that appeared only in video games, and has never been part of any official set. His creator was also a bounty hunter.
4-LOM was assigned to work on the Kuari Princess where he became a translator to the ship's wealthy passangers. He found his work undemanding and after the Kuari Princess's computer altered his programming, he began a ruthless personality and started to steal from the passangers and their luggage. He then left the Kuari Princess forever and began a thieving life, and then Jabba the Hutt altered his programming further, he became a succesfull bounty hunter protocol droid and became partners with Zuckuss.