According to Marisa though, Reimu was abandoned by her parents when she was a kid for being crazy.

That's why, well, why Marisa always cares for Reimu like she's her parental guardian.

Ah, that reminds me. I called that Marisa here the other day.

She bursted out crying all Waaah, waaaah as soon as she saw Reimu's face. Man, surprised the heck out of me.

I can never understand that weakness of them humans.