Dark Old Demon

Roy's life was nothing special. The only thing commendable was the last few moments when he saved a mother and her child from a drunk driver.
...
It's really an egg! Damn it, what kind of monster have I become? Did I fall into Hell instead of making it to Heaven??
Join Roy as he ventures through various worlds with the Custom Made Demon King System—a system that allows Roy to draw anything he can imagine and create it through exchanging souls!

Custom Made Demon King

Roy felt that this trap devised by Arantir and Astral's group was very… interesting!

When he saw Arantir's undead army being driven out of the fortress through the Demon Eyes, Roy had believed it for a time. If they were really just acting then, then Roy had to say that their acting was the best of the best. Precisely because of this, after Arantir left the fortress with his troops, Roy did not pay much attention to him and focused the investigation of the Demon Eyes on the infection process of the T-Virus.

This allowed Arantir to complete the operation of replacing the original with a fake under his nose.

Plague Monarch, Artificial Disaster