Saikin Koi Shiteru?

Saikin Koi Shiteru? is an otome game, developed by Microvision and published by D3Publisher, which was released in Japan in 2009.

The 17 year old nameable heroine transfers to Seiran Academy and falls into a deep pool that’s just sitting right at the entrance, and meets some…mitochondria?

It turns out that everyone she meets has them but only she can see them. She names them Saikin (bacteria) and uses them to manipulate other peoples feelings (with…good intentions).