In any videogame: What would be the coolest side-character to play as?

If you wouldn't be the main character, which side character would you wanna be and why?
Thinking about Pokémon I believe being Cynthia would be quite epic, waiting to ruin peoples careers. :D

Other than that I wouldve loved to see a campaign playing as Jack of Blades from Fable. The character is super evil but very intruiging and seeing his view of the world would've been super interesting to me!