Well, it's possible that Raki, being the fag that he is, understands that Priscilla, despite being an awakened one, is still just a child yearning for affection (a disturbed kind of affection, but yeah). He probably saw how fragile her emotional condition is and so he took it unto himself to take care of her.
That, or Raki just realized the wonders of being a loli-con within those 7 years that they've been together. ^_^
What I'm more interestered in, is what Riful has been planning. She mentioned a plan that will turn the tide of balance with the three remaining super-powers (Rifiul, Alicia, Easley-Priscilla). The fact that she needs a claymore that can detect Youki is intriguing. I'm wondering if Riful is searching for a certain "someone" or " something".