Biochemical Pokémon

A human discovered a cross necklace from a meteor that could not only exchange killing points for various biochemical virus substances, but also travel through various novels, animations, and comics. See how he creates his own myth. Rest assured that the protagonist will definitely have a harem. This is my first novel. Please forgive me for the shortcomings in the novel. This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.