Gemnemo

ゲムネモ

Gemnemo is a sentient, intelligent terrorist microbe who became the first bacterium to master sorcerology.
He devised a "hyper augmented method for accelerated cytological division," or, put simply, a way to enlarge and strengthen living organisms. He arrives in Hellsalem's Lot and convinces Riel to undergo his procedure, aiming to become stronger and seek revenge on those who bullied and hurt him due to his frail body.