What Pokémon Would You Main If UNITE Added It Tomorrow?

Ancestrix

Let’s say UNITE dropped a surprise update and added ANY Pokémon from the whole Pokédex no limits.
Who would you main and why?
Bonus: What role do you think they’d be (Attacker? Defender? All-Rounder?)

I’m torn between Spiritomb (just imagine the chaos) and Serperior (long-range vines would be 🔥).

Curious to see if y’all would pick legends or stick to classics!