Sayuri

This adorable little blonde girl showed up out of the blue the day that Zero appeared, innocently asking Katana what he was going to call him. For whatever reason, this child, armed with a pink coat, a bunny plushie and a big smile, refuses to go away, following the not-so-welcoming boy wherever he goes with the claim that she is his "friend". She seems to seek out others who surround Katana, searching for more friends for him, asking Aiko and even Takumi if they are friends of his when she runs across them in the junk yard. She always seems to know more than she says, giving nothing but an innocent giggle when asked why she doesnt go home and where her parents are. (from Wikipedia)