Isekai kara Kita Kimi to Tomo ni Sugosu Nichijou

I'm going to start living with an elf!? Eiichi Oribe, an unemployed young man at the bottom of his life, picks up a mysterious stone in the park one day. When he opens his eyes, he finds himself on top of a giant tree with a beautiful elf in his arms! Eiichi tries to save her, but they fall from the tree and he loses consciousness on impact. When he wakes up in the hospital, he sees the elf Tia and Kurokawa, who claims to be a public security officer. Then he is told a shocking truth… followed by a sudden confession from Tia! What will be Eiichi's fate? (Source: ComicWalker, translated)