Exetior is the main antagonist of the Sonic.exe: Nightmare Version series, and was an upcoming EXE but never made it outside a few concepts. Exetior is said to be an Arch-Demon who escaped from a hellish prison and hid on Mobius, in the body of Sonic the Hedgehog. He is the former Highest and one of the creators of Mobius. He wants to demonize the inhabitants of Mobius, gaining his army, and win Mobius from the Highests for his own control only.
Exetior is created and owned by JaizKoys.