Duncan, primarily known as Man-At-Arms, is an advisor to the ruling planetary monarch of Eternia and head of the Royal Guard. He is known as a "master of all weapons", as well as being an inventor.
Turtles of Grayskull[]
While searching in the Swamp of Gangoon for the missing He-Man, Man-At-Arms, Teela and Roboto find themselves battling a mutated Trap Jaw and a horde of Mousers. Just as they are about to be overwhelmed by the replicating robots, the Ninja Turtles arrive. The two groups combine to defeat the Mousers and capture the mutant now called Mouse-Jaw. Leonardo introduces himself and his brothers, and then Man-At-Arms asks if they are familiar with the purple mutagen he found. They realize it is mutated mutagen and dangerous, so the two teams join forces. By The Power of PIZZA!