Sooo this would be the first time Yume (age 15) met Gakupo... And why she hides behind Len or Haku when he comes around...

It went something like this,

Yume: So you're Gakupo-kun?
Gakupo: Yes, you must Yume-chan?
Yume: Yep-yep! Are you really a Samurai??
Gakupo: Yes, yes I am... Want to see my sword??

Why he stabbed Kaito before showing Yume the sword I dunno.... I thought it was funny