Seirei Ai

Young college student Shido Itsuka had one goal in mind this school year: lay low and survive. But between his parents' recent deaths, his little sister Kotori's tantrums, and a weird girl from his class stalking him, Shido thinks that his school year will be miserable.
That will have to wait, however, because when a spacequake threatens his city and almost kills Kotori, Shido realizes that there's something much, much bigger coming to Japan.
Something... out of this world.