Rotom don't have a gender, it seems more like can't than won't for EVA, he points out. Anyway, I caught it in Goldenrod near an electronics shop, if you don't mind staying up late it's really not hard.

Teaching Mesmer is the fun part for Teller; everything else is just business. It doesn't take him long, anyway, to replace the Solus-shaped hole he's making with Steven, and he lowers his hand to examine the Rotom carefully, before he nods with a satisfied little, "Hypno."