You should practice in your vessel form with your god, too. I've known some shinki who turned into forms that their god had no idea how to wield, and it's much better to try a few things before you're face to face with an ayakashi.

[Hakkai clears his throat: well, yes, it had come rather easily to him, but then, he's been discovering that borderlines are far from the only magic he can do.]

... I seem to specialize in that kind of thing.

[He curves his hands over one another, in front of his chest, summoning just enough chi to form into a glowing sphere between them.]

So it's possible I had training that I don't remember! Being able to summon a borderline at all in the first session is very impressive.