I'm a Rin guy usually but the lack of zettai ryoki is disapointing here so I guess the absolute insanely cuteness of our kouhai Mashu will have to do.
And yeah, there I went and spoiled myself by watching this since I'm stuck at the beggining of Camelot in the game. Knowing who is the Servant Mashu merged with was something I was not expecting so quickly but at least now I've got that out of the way