Pluto

Pluto (Charon) appeared in "Saving the World From Ruins!" albeit not in a speaking role. He is seen briefly in Team Galactic's base.

Charon made his first full appearance in "Gateway to Ruin!" along with Saturn where they were trying to find the Spear Pillar in Mt. Coronet.

Charon made another appearance in Team Galactic's finale from "Unlocking the Red Chain of Events!" to "The Battle Finale of Legend!" where he assisted in the final stages of the Red Chain project. He is not arrested, unlike the other three Commanders at the end of the arc, and presumably escaped.

He is often seen with a laptop computer and does much of the technical work for Team Galactic's plans, such as monitoring energy levels and other statistics. Compared to the other Galactic members, he is the most laid back and upbeat, which often causes one-sided squabbles between him and Saturn.

(Source: Bulbapedia)