Princess Lucia [Manga]

Koizumi Yuta is a 14 year old boy who has quite a bit of a problem. The demon princess of the magical world, Lucia, has to procreate with him. That child would have the ability to engulf the entire world for 7 whole days. Mikamoto El and Kasukabe Rie are the two angels assigned to make sure that doesn’t happen. Kasukabe Rie happens to be the girl he likes. Just how is he going to survive this ordeal?