Leonhart
Imagineer
Henry's Journey said:But I still want him to pull a Charizard return even if it's "fanservice" XD, I feel like Greninja should have been left "in training" rather than released, Kalos is the only region where Ash doesn't "own" a starter :/ (well and Galar so far lol).
I feel that he's the most likely to return regardless of whether he's treated as "in-training" or officially released, but also one of the least deserving of a comeback since he was already better developed than perhaps 90% of Satoshi's other Pokemon.