Original

The following fiends can be unlocked through various means by capturing other fiends for the Monster Arena.

Earth Eater

Unlock two Area Conquest fiends.

Greater Sphere

Unlock two Species Conquest fiends.

Catastrophe

Unlock six Area Conquest fiends.

Th’uban

Unlock six Species Conquest fiends.

Neslug

Capture one of each fiend from every area in Spira.

Ultima Buster

Capture five of each fiend from every area in Spira.

Shinryu

Capture two of each underwater fiend in the Mt. Gagazet caves.

Nemesis

Capture ten of every fiend across Spira and defeat all the other creations in the Monster Arena (including Original, Area, and Species).