Game Isekai de Mamono ni Tensei Shiteshimatta Ore, Sensei de Oshidatta Heroin Ohirotteshimau

Upon waking up, I found myself reincarnated into the realm of a game I had previously played in my past life. To make matters more complicated, I had become a monster that is antagonistic towards humanity! With no other option, I chose to live quietly to avoid detection by humans, but... I discovered the heroine, Noa, who had been my oshi in my previous life, collapsed close to my dwelling!! After I took care of her and ensured her safety, my oshi named me "Rei," prompting me to commit to protecting her for eternity and accompany Noa. I also encounter other characters from the game and observe Noa's development, but... the real Noa appears to have a clingy nature and harbors a rather... "heavy" love? This is the tale of my journey, reincarnated as a monster, as I face challenges alongside my beloved oshi.