SkullTyranomon is a Bone Soldier Digimon whose name is derived from "Skull" and "Tyrannomon". With its body being converted to 100% organic-less bone material, it has improved its armor and defensive capabilities by tenfold. It reinforces its body with bones from other Digimon to strengthen its armor, so it is always on the search for bone materials to use to reinforce its body further and further. Originally, it was created by a hacker from many Dentimon and IronDentimon to test out the fusing of many Digimon of different types, but it became resistant to the commands given to it. It uses 2 large mortars on its shoulders named "Vanguard" and "Gigamo" to attack its foes. It has no control over its actions since it is completely bone material, so its actions are completely out of its control.
- Gigamo Flare: Launches a bright red glowing missile at the target and illuminates the sky around it with a very bright, red flare of fire.
- Vanguard Flare: Launches a bright blue glowing missile at the target and illuminates the sky around it with a very bright, blue discharge of pure cold.