Manga by author Ogawa Maiko

Kouichi has looked forward to becoming a high schooler for one reason: to help continue his grandfather's coffee shop. But on the first day of school, a strange girl wearing an eerie mask tells him that she has come to take his life. She tells him that the heart beating within his chest is her own, and that she is an alien invader who has come to take over the world.

English: My name is Suzaki Aiichirou, a lone wolf and I live to fight! However, one day an annoying girl came to my house and challenged me to a duel ... and since that day on my life has completely changed. This is a story about the born of a brand-new world.Spanish: Soy Suzaki Aiichirou, un lobo solitario. Mi vida es, todos los dias, peleas y rias. Sin embargo, un da todo se acab... "uwaaa~!!!" Un beb misterioso apareci de repente en mi casa. Adems, una molestosa espadachn se mudo a mi casa. Y as comienzan mis nuevos das. Un encuentro comenz, uno que crear un nuevo mundo. Una pequea historia, tuya y mia, sobre el nacimiento de un nuevo mundo.+