Yasutaka Fukuoka was a teacher at Tategami High before it was discovered that he was also an Invader sleeper agent.
Yasutaka was a red Invader with fake identity papers and armed with a chalk-shooting gun.
Despite being Megumi Kurogane's favorite teacher, Yasutaka was hated by most of the student body. After he was forcibly transformed into his true form he unwillingly attacked Megumi and the Gate Keepers. Shun Ukiya was forced to slay him in front of Megumi.