Lefty

Lefty is a gnome rogue, and is part of Theldren's team of gladiators at the Blackrock Depths arena.

His weapon, Lefty's Brass Knuckle, can sometimes be found in the Arena Spoils after defeating Theldren's team.

Monk?
Is unknown what class Lefty is, if any, but he has been assumed to be a rogue. However, his abilities and choice of weapons make him more similar to a monk, although the Monk class didn't exist when he was implemented.