Just finsihed Ep.7 and the first thing I want to write:
Who's U.N. Owen? A 495 years old witch? Why am I imagining a small girl with a red goth-loli fashion that can use Laevatinn as a plaything?
Still, tricks aside, after playing this episode I can say that the whole ep.6 is a troll. The whole ep.7 suggests that Yasu=Shannon=Kanon=3rd Beatrice, meaning BATTLER, Jessica, and George is battling over the same person.
Following Yasu's life story, I think Gaap is a personification of Yasu's mental disorder caused by the fall which probably damaged the brain somehow, making Yasu somewhat of a klutz (yet maintaing the high intelligence). Also, I think "Shannon" really existed, but somehow went away and her role was taken by Yasu (at the moment Yasu depicted becoming a witch). My point is, if this flashback is real, then I think I can sympathize with why the killings occurred.
Edit: Also, there is still one major riddle that might change how we view the whole story: WHO THE HELL IS BATTLER?