Antikeeper

Antikeeper is Gatekeeper's brother. Like Gatekeeper, he was a human until he came into contact with a Nightmare crystal. His power is on-par with Gatekeeper, and after two fights and a lot of time spent in dormancy inside Gatekeeper's mind, Gatekeeper decided to let him go on the condition that they were allies. They grew to be close friends afterwards.

His Crystal is the Nightmare Crystal, and he is the God-Tier entity of it.

He uses fear tactics and hooked blades to fight, and a side of Ark abilities, but shifted towards his darker Crystal type.