Another DTA entry.

This girl is a daughter of an old retired mercenary. She works for an organization which is a kind of asassinsins guild. She is one of coordinators for this guild, she manages tasks for killers and mercenaries and satys in touch with them.
Her codename is Ralph and though many knows her tender voice, nobody knows for sure who really is, what does she look like and what is her real name.
(But I will tell you this secret, her real name is Robin)
Yes, this is Kai's step sister.