Kerlo was a criminal employed by Shoto Eyefire, a Defel crime boss who controlled Horn Station. He was a thug and professional gunman, and usually got into fights because of his brute temper.
One day, Kerlo demanded money from a man he took to be an itinerant miner, and challenged him to a showdown with blasters when he refused to pay up. The miner was in fact an undercover Jedi Knight, who made short work of him, taking the thug down with a blast before Kerlo's blaster had even cleared its holster.
Kerlo survived the incident, which was promptly reported to Eyefire. His defeat piqued Eyefire's interest, prompting him to challenge the newcomer himself, a decision which ultimately led to his downfall.