Gruell is the ruthless and sadistic Triceraton Tri-Sports Arena master. He appears in the 2003 TV series episode "Turtles in Space, Part 4: The Arena". He was voiced by Wayne Grayson.
Biography
The slavers arrive, lead by the corpulent Gruell, a cruel task master that utilizes an electric whip to keep the gladiators in line. Gruell orders the Turtles to become "practice dummies" so the other warriors can practice their moves - the slaver orders the ninjas to not use their hands. The TMNT comply with this order and are attacked by their fellow slaves - but the ninjas aren't about to take punishment without a fight, so they use their ninjutsu skills and teamwork to kick and dodge their opponents into submission. This strategy angers Gruell, who uses his whip on Raph and orders the Turtles to stop cooperating - but the temperamental Turtle manages to disarm the task master and informs him that they always fight as a team. Gruell, in a panic due to being disarmed, offers extra portions for their next meal to any gladiators that can defeat the TMNT.
Traximus faces off with Leonardo, and the mutant quickly defeats his saurian foe. Don, Raph and Mikey also win their battles and the TMNT earn the respect of the gladiators, but by now Gruell and his guards have regrouped and they get the slaves under control. Later, the Turtles are waiting in line to get gruel from Gruell, their last meal before their epic battle in the arena. However, once the Turtles get to the front of the line, the slave master tells them that there's no food left and they will have to go hungry.
The gladiators are assembled in the pit and given weapons, save for the TMNT, who Gruell refuses to arm.