Hmm... How to explain this in a way that you'll get.

[He does seem to be considering.]

Well, you're a dragon now. I guess the rumors about the bloodlines were true. Something must have awoken the blood for you and your siblings. Dragons are mostly beings of pure mana inhabiting flesh vessels. Because you ate my foci, you absorbed them, and I had command over them so now we have a full pact mark.

[He absolutely just raised his hand and pulsed her pact marks.]

And you seem to have a new human form. I think that about covers it.