A Terrellian boxer was a boxing opponent whom Chakotay sparred with while a cadet at Starfleet Academy. During one match, Boothby, who used to coach Chakotay, warned him that he was taking the Terrellian too lightly and should let him punch himself out. Chakotay did not listen to his trainer and was knocked out by the Terrellian in round four.
The original Terrellian was only mentioned in dialogue.
In the final draft script of "The Fight", the Terrellian hologram was described as wearing similar attire to Chakotay and being "the same size as Chakotay, but built more powerfully, looking far more dangerous."