Tonchiki has an odd bulbous body. His head is brown and bumpy. He has brown antlers coming from the top of his head and blue eyes. His body is a light blue colour. There are two beige donut-shaped prominences on his body that are connected to two other long red strands that end under his eyes, similar to a chicken's wattle. He does not have any arms. Tonchiki's mouth appears to be similar to a beak, and can only move up and down.
Tonchiki is the loyal servant of Maoh and creates various monsters to retrieve blood for his master, as well as to generally cause mischief. First appearing in Episode 1, he reminds a seemingly amnesiac Maoh of who he is and his plans. He is usually quite cowardly, but did fight Greenman in episode 50 when forced to by Maoh. He was defeated, but ran away before he could be killed. When Maoh decided to fight Greenman directly, he summoned Tonchiki to take the children to the underworld after he turned them to stone. When Greenman went to the underworld, he only found the stones. After Greenman defeated Maoh and revived the children, Tonchiki reappeared. He then apologised to Greenman, before teleporting away.
- Tonchiki has never grown to giant size like some of the other monsters.
- Tonchiki inadvertently saves Greenman from certain death against Iho Killer by stepping on one of the Green Calls, stopping the hero's paralysis by repairing his machinery.
- A running gag in the series involves Tonchiki being repeatedly knocked over, usually by Maoh or the monsters.