I honestly think out of all the beasts Wizard was stranded with, he might have gotten along with Eternal Sugar the most, if only because she didn't seem to care about him being there + might have been fond of taking care of children just like Shadow Milk once did :)
Hmmm I'm actually not sure tbh!
We'll have to wait and see what Eternal Sugar's whole deal is in terms of abilities, personal goals, and overall personality. We don't know a LOT about them. And while we can infer some things from what bits and pieces we currently have, there's still to many gaps for my personal liking.
My guess: maybe something similar to the Lotus Eaters mythos?
But that's just my personal speculation atm.
As for how they would have treated Wizard Cookie? Well, my current mental image of Eternal Sugar has them not really caring too much about him being present. Maybe fussing over him just to have something to DO, but it would be incredibly condescending. I don't think Wizard would like ES very much. He wouldn't like being talked down to.
He would be a form of entertainment, if anything. But again, that's just based off my own observations and speculations.
