Choujinki Metalder (OC Male Reader) X Rosario + Vampire

In earlier, Dr. Koga's visits the funeral of his only son died during World War II. When Dr. Koga goes in Former Japanese Army Imperial Headquarters to secret shelter and he found a powerful android but he looks perfectly like a human and his face of Dr. Koga's only son. Dr. Koga named him is Ryūki Hirai, Superhuman-Machine Metalder. Later, Ryūki discovered of his first time at the school: Youkai Academy, so he decided to be enroll. But will the monsters ever going to exterminate him?

WARNING:
Some of the bad grammars and mild suggestive themes.

DISCLAIMER:
I do not claim anything about Choujinki Metalder or Rosario + Vampire.