Lysandre

Lysandre is the main antagonist of the Pokemon video games Pokemon X and Pokemon Y. He is the boss of Team Flare.

History
Lysandre is first met in Lumoise City in Professor Sycamore's lab. Lysandre shows enthusiasm towards the player and their friends, applauding them for embarking on the Pokemon journey and calling them the "chosen ones." He also reveals that him and Professor Sycamore are close friends who carried out research together in the past.

The player interacts with Lysandre during their journey, learning of his ideals: to create a beautiful world, one without any suffering. Lysandre tells the player the story of the King of Kalos, who attempted to destroy Kalos via the use of a secret weapon as vengeance for humankind's horrific acts during a huge war. He also reveals that he is a descendent of the King's younger brother. He repeatedly expresses remorse for mankind's condition, similar to the sentiment which the King of Kalos felt, and tells the player that be believes that mankind is selfish and constantly takes what is not theirs. He says that the acts of the King of Kalos were "reprehensible," but admits that these actions were what allowed the world to be "cleansed of that era's filth."

He contacts the player occasionally to talk about Mega Evolution and continues to talk of "cleansing" the world. Eventually, he reveals himself as the leader of Team Flare, whose motivation is to repeat what the King of Kalos once did and reconstruct the world. This would mean eliminating all humans and Pokémon, letting only those of Team Flare survive, and creating new world consisting purely of Team Flare's members. This mindset is very similar to the Diamond and Pearl antagonist, Cyrus.

Unlike Cyrus, however, Lysandre shows genuine remorse for having to destroy all these lives, openly crying in front of the player. He claims that this path was the only option due to resources, space, and energy being limited on the planet. Lysandre argues that the number of Pokémon and people on the planet had reached an unsustainable level, and that if Pokémon and "corrupt" people continued to exist in the world, it would lead to even more suffering. He believes that Pokémon are wonderful beings, but that humankind abused them in wars and used them in theft, and, thusly, decides that destroying them is the only answer.

When facing the player, he says:

"When there is only one of something, it can't be shared. When something can't be shared, it will be fought over. And when something is fought over, some must survive without it. The only way to create a world where people live in beauty, a world without conflict or theft, is to reduce the number of living things."

This summarizes Lysandre's vision and also the outlook which Team Flare shared.

In battle, Lysandre is confirmed to have access to a Mega Ring, like the player's.

When defeated for the final time, a desperate Lysandre tries to force immortality on the player and their companions (in Pokémon X) / to destroy the entire building by firing what little power remains in the ultimate weapon (in Pokémon Y). The blast from the weapon destroys it, causing the building to become buried in the rubble. The player and their companions are able to escape the blast. Lysandre's fate, as well as the fate of the individual members of Team Flare, is left ambiguous. After these events, however, Team Flare disbands as an organization.

After the event, Professor Sycamore apologizes to the player on behalf of Lysandre. Professor Sycamore thanks the player for thwarting Team Flare's plans, and says that, in doing this, the player was able to "save" Lysandre. Professor Sycamore also says that he is partially responsible for what Lysandre did, as he never talked to Lysandre directly about how flawed the man's plans were.

Pokémon Adventures manga
Lysandre makes his first appearance in Lumiose City, where he is visiting his friend Professor Sycamore's lab.

Trivia:

 * Lysandre has similarilties to the Diamond and Pearl  antagonist,  Cyrus, with his goal of creating a new world. They also have two similar  Pokémon:  Honchkrow and Gyarados.
 * His role of being Team Flare's leader can be considered obvious as he goes on long tangents about beauty and global destruction, has fiery red hair, dresses like someone associated with Team Flare, and owns a cafe that Team Flare hangs out at.
 * Lysandre is the inventor of the Holocaster.
 * Lysandre is the descendant of the brother of King AZ (the King of Kalos). King AZ was similar to Lysandre, as they both used the Ultimate Weapon in an attempt to "beautify" the world, or purify it from what they deemed as "corruption."
 * Lysandre and Professor Sycamore studied Mega Evolution together and, judging by Sycamore's praisal of him during the plot (namely, in his Lab and in Lysandre Caf é ) as well as his reaction to Team Flare's disbandment, the two are most likely friends.
 * Lysandre is one of three people in the main storyline to use a Mega  Pokémon d uring battle, the others being the Gym Leader Korrina and the Kalos Champion Diantha. After defeating the Elite Four and Diantha, your primary rival (Serena or Calem) gains the ability to use Mega Evolution as well.
 * Lysandre's cybernetic suit, the Lysandre Machine, was meant to be used to drain Xerneas/Yveltal's power into the ultimate weapon.
 * Elite Four Malva was a member of Team Flare and therefore knew Lysandre.
 * His Mienshao is the only Pokemon on his team that isn't a dual-type.
 * Has yet to show up in the anime.