Cartucke the Demon Lord of the Void. His main appearance was in the level "The Fiend" in Myth 2: Chimera--this is where Fenris, Kyrilla, and other heroes faced him and drove him from the planes of the Myth world. It is uncertain what type of sway or alliance Cartucke had with the Fallen Lords--but some hints throughout the storyline point to him possibly being from the Fetch's homeworld. This is speculation of course, but it would make sense since the Fetch are allied to him, the Fallen Lords, and Soulblighter. Perhaps his alliance with Soulblighter was a fullfillment of Soublighter's promise to send the Fetch home, but after Kyrand's intervention, Cartucke and Soulblighter didn't have a means to accomplish this task. It should be noted that Cartucke was probably weaker when he faced Kyrilla, needing a gateway to be able to step into the myth world, and he could not transport the Fetch back home by himself.
Cartucke's model often appears in various plugins as he is a unique creation among the Bungie team.
He was a black demon that could turn people to stone and cast many bolts of red electricity. Cartuke also had power to create undead, manipulate people through illusion, and summon mahir. Cartuke may have other powers not yet disclosed, but we will never know as he was banished from the Myth world by Fenris, Kyrilla, and ne'Ric.