I thought this was neat so I'll chuck it in the comments, here's Akuyaku Reijou Tensei Oji-san art from the mangaka of Endo and Kobayashi's Live Commentary on the Villainess.
Okay, that was unexpected and much more interesting than just summoning. I wonder who the voice belongs to. God? His daughter? His daughter who is now a god? I have no idea.
I'm guessing Lady Grace would naturally have fire, while Kenzo has water as an attribute. Because they're merged, an ancient dragon. Now we're seeing some more cheats!