Ghetsis

Ghetsis is the main antagonist in Pokemon Black and White, as well as the adoptive father of N. He is one of the Seven Sages of Team Plasma. All along the story, he pretended to serve N and to fully support Team Plasma's utopy, though he often lets slip that he serves his own interests. In fact, his true goal is to be the only person in Unova to have Pokemon, so that he would be able to take over the entire land. To do so, he manipulated his own son as a puppet-king of the Team to make him capture Reshiram or Zekrom, so that he would be able to use them.

Pokemon Black & White
He was first seen in Accumula Town talking to the locals that they shouldn't enslave Pokemon. You encounter him several times telling everyone to send their Pokemon to Team Plasma to be released back into the wild.

After the player beats N in his castle, Ghetsis will come up and say that N was a disappointment losing to the player, and it was revealed that Ghetsis was using N for his own evil deeds, calling him a good-for-nothing boy, warped, and defective. After that, he will battle the player in a rage. When defeated, he will be taken away by Cheren and Alder. After the game is completed, it is revealed that he escaped thanks to the help of The Shadow Triad, his most faithful and loyal servants.

Black 2 & White 2
In Pokémon Black 2 and White 2, Ghetsis is the leader of a new Team Plasma. This version of Unova's villainous team is more straight forward with their plans to rule Unova  by freezing the region rather than freeing Pokemon. He has recruited Colress and Zinzolin to help him.

He first appears at the Giant Chasm where he announces that he will awaken and use Kyurem to freeze the land. Upon being encountered again, heorders Kyurem to kill the player, but N destoys the attack. Ghetsis fuses N's dragon with Kyurem, making it even more powerful and forces the player to battle it. Kyurem escapes, and the player must battle Ghetsis. Upon losing, he suffers a mental breakdown and is escorted away by a member of the Shadow Triad saying he has "lost control".

After the game is completed the Shadow Triad are found Icirrus City. They state that Ghetsis is no longer capable of doing anything let alone commit further criminal acts, implying that this loss of control may be permanent.

In the anime
Ghetsis is confirmed to appear along with the rest of Team Plasma in the upcoming Best Wishes: Episode N arc of the anime, which is due to begin on January 17, 2013.

Trivia

 * His strongest pokemon is a Hydreigon at level 54. However Hydreigon's previous evolved form; Zweilous evolves into Hydreion at level 64, so his Hydreigon is underleveled.
 * Ghetsis is the only antagonist that uses a Pseudo-Legendary Pokemon during the final battle with the main hero.
 * In Pokémon Black 2 and White 2, Ghetsis becomes the first Trainer in the main series games to use seven Pokémon to battle, due to controlling Kyurem and having a party of six Pokémon. Overall, he is the second Trainer to do so, the first being Greevil in Pokémon XD: Gale of Darkness.
 * The Ghetsis Stick disables Poké Balls, which he uses to stop the player from catching Kyurem while it is under his control.
 * In Black & White, all his pokemon are at level 52 and his strongest (Hydreigon) is at level 54. In Black 2 & White 2, his pokemon are at level 50.
 * His attempting to freeze the player alive was often mistaken on the internet as trying to impale them with icicles, before the translated versions were released.
 * On the Internet, he is known as "Dennis" due to people mishearing the chanting happening during the battle with him. It can be heard at about 1:32.

Battle Video
thumb|350px|left|Battle with Ghetsis