Grannewt Unova has given this much thought

not too happy with how this piece turned out :'> but, I'm still impressed that I was able to make it!

Image I based this on under the 'Keep reading'

Alright.. You're all gonna regret this! Grannewt's pretty nonchalant about most foods, having a serious nature... Except when she's introduced to some human delicacies

This is a quick doodle showing Grannewt without her aged look! She can go back to looking like this: If Grannewt decided she wanted her youthful appearance back, she would have to use the move 'Recover' on herself for a long period of time. This would not reverse the mutation, it would just tighten-up and plump her skin out making her look young.

That being said, Grannewt (aka Unova) and her brother Mewtwo (aka Kanto), probably don't give a toss about how others view their appearance, which is why they choose to look aged

They're Immortal after all! If they wanted about 80 years of a youthful look during eternity, I'm sure they would do the Recover method! ^^

I've always said for my canon, Okita would take on Newt's ability to take a hit. As for Chilli, He would take on her speed, just... Don't challenge her, pipsqueak