Charon

Charon is one of Team Galactic's commanders.

In the games
He appears in Pokemon Platinum at various points in the game. He befriended and discovered Rotom. By the end of the game, Charon is arrested by Looker. The player doesn't battle him at all in the game but you do see him only in the building once in the lab underground. He is at the beginning at Valley Windworks. Later in the game, He is in Team Galactic's HQ and with Saturn. At the very end of the game he is the boss and he's at Stark Mountain.

In the manga
He appeared near the ending of the Diamond and Pearl Arc. Though he quickly disappears. Though he leaves a notebook containing important info.