Believe it or not, William wasn't always an anthro jackal knight. He started off as Billy, a gunslinger from a post-apocolyptic world. The post-apocolypse part stayed but over time, Billy's weapon of choice became a sword. His name became William to be less derivative... and the Billy reference didn't make as much sense since he was no longer a gunfighter. As for the anthro jackal part? I blame the "After the Bomb" add-on to the "Teenage Mutant Ninja Turtles" roleplaying game from Palladium games. It just put the idea into my head.