In the games
In Pokémon Black and White 2, Colress is first encountered in Castelia Sewers. He is met again at Castelia City, where he tells the player that he disagrees with the old Team Plasma's goals to liberate Pokémon from humans. The player re-encounters Colress on Route 4, where several Crustle block the path. Colress uses his machine to drive the Crustle away and challenges the player to a battle. Colress is once again seen as a participant in the Pokémon World Tournament, matched against the player in the final round of the tournament. He is later encountered on Route 22. Like usual, he talks to the player mostly about Team Plasma.
Later on, during the battle against the new Team Plasma on the Plasma Frigate while at the Giant Chasm, Colress is seen in a chamber, where he reveals that he joined Team Plasma to pursue and research the true strength of Pokémon. After he is defeated in battle, he allows access to Ghetsis's chamber, wanting to see if the player can stop him.
After the player enters the Hall of Fame, Colress continues to dwell in the Plasma Frigate; however, he and the other Team Plasma members have decided to put an end to their ambitions. Colress remains in the chamber when he first met the player on the Plasma Frigate; there, he enganged a battle with the player and will give the player a Master Ball once defeated. He will then move to the stern of the Frigate, where he will battle the player once per day.
He makes a brief reappearance in Pokémon Sun and Moon, where he gives the player TM43 on Route 8. After the player becomes Alola's first Champion, he will give them the Genesect Drives, and can also be fought in the Battle Tree. On his and the player's first meeting, he tells them that he's still researching the true power of Pokémon, but now believes that said power comes from the bond of a Pokémon with its Trainer. He reveals that he come to Alola so he could research the Z-Ring and if it's more effective at drawing out the power of Pokémon than the Mega Ring, and also appears to be interested in the Poké Pelago.