Chimera

Chimera is a "bizarre magician", a magic god, who dwells in a territory beyond a certain layer of the world.

Etymology
In Greek mythology, a chimera is a creature that is part lion, part goat and part snake or dragon. Its body is that of a lioness, the snake or dragon head was its tail, and a goat head just popped out of its spine in the middle of its back. It also breathed fire. According to the myths, it was eventually slain by Bellerophon with the help of the winged horse Pegasus.

Appearance
Nothing is known about what it looks like.

Magic God Othinus Arc
They are mentioned in passing, alongside the Zombie girl, by Niang-Niang as one of the Majins present in the hidden Phase with the rest of GREMLIN.

St. Germain Arc
It is unknown where Chimera is when High Priest, Nephthys, and Niang-Niang decide to enter the world once again using Zombie's spell. It can be presumed that it was defeated by Aleister when he broke through GREMLIN's secret layer.