It was a really good episode. Much needed background info of Saya and Hagi's past. Quite conclusively indeed. It was an interesting past, to say the least.
Edit: Oh, and obviously it also revealed something very interesting about Saya's inherent powers. She's not at all just a killing machine, and she's probably very similar to Diva, in the end. I wonder if it's only her personality that separates her from Diva.