Ai ga Shinu no wa Kimi no Sei

Who is the one inside him? When Aoi was little, she confessed to her childhood friend Isumi but can't remember his reply for some reason. She asks him to meet her at their old secret base so she can confess again, but something unimaginalbe happens to Isumi before her eyes. When she comes to, he's back to normal. But only Aoi knows... that there's someone else inside him! (Source: MANGA MILLION)