Ainz Ooal Gown

Ainz Ooal Gown (アインズ・ウール・ゴウン, Ainzu Ūru Goun) is one of the main characters of Isekai Quartet. He is the leader of the Great Tomb of Nazarack. Whenever his favorite MMO YGGDRASIL shut down, he found himself stuck in a world similar to the game, making him the isekai character in his universe.

Personality
A wise and powerful king who is beyond merciful, cruel to his enemies, and a hero...The personality he displays to his fellow Guardians, whom he sees as children. While he appreciates them all, he finds them to be a bit stressful and tiring with their praise, and is glad they're now seeking to make friends with others. Allowing him the opportunity to be a normal person, particularly with Tanya alongside Subaru and Kazuma.

He sees this new world as good for nothing but not necessarily bad, and finds interest in his other classmates. Taking pride in his power and willing to even help his fellow Isekai on Field Day protecting them.

Powers & Abilities
As a Level 100 being he is absurdly powerful. Capable of doing many things from shielding, spells, great knowledge, and so on. He is one of the most powerful beings in his world, and the same in this one sans a few others who may equal him.

Snow Spell: He is capable of creating an entire snow day with his spell wowing everyone.

Shielding: He can make a powerful shield strong enough to even repel the Mobile Fortress Destroyer itself.

Teleportation: He can teleport to different areas as he pleases.

Flight: He can float around in the air with this spell.

Undead Summoning: As a lord of the dead he can call upon skeletons to protect others or fight for him. Even use them as shields.

Despair Aura: Can cause others to lose concentration and become fearful.

Aura Vision: He was capable of seeing the powerful curse 'Return by Death' within Subaru.

Energy Detection: He could gauge the amount of power from Tanya's own spell stating it to be above 8th Tier magic.

Emotion Suppresor: Suppresses his emotions.

The Guardians
His 'children' as he calls them. He does his best to guide them and always tries to help them out. And while grateful to them, he finds them slightly tiring from their views of him. Also a bit embarrsed by Albedo's and Shaltears affections toward him. Still, he considers them family and is glad they're reaching out to make new friends in this world.

Tanya
Originally Tanya thought of him as Being X and wished to face him. Though eventually he was able to convince her he wasn't, and the two learning they were both Isekai people. Soon becoming good friends with her though somewhat fearful were it not for his emotion suppressor. He also plans with her such as Field Day and aids her. Like Kazuma, he guessed she was from a war world.

Kazuma
He is on decent terms with Kazuma. The adventurer helping him out with Aqua and when Raphtalia both whom tried attacking him.

Subaru
He finds the boy very interesting as he notices a strange dark aura around him. Apologizing when touching him, and is on decent terms with him. He also points out Subaru's hypocricy of his Battle Maids as he has two Demon Maids around him. In the opening they both laugh awkwardly around each other.

Aqua
He is a bit on guard of her as she easily causes him pain having never expected such a thing from her. He finds her annoying with her purification attempts yet is still kind enough to defend her from Tanya's wraith.

Megumin
He respects Megumin's powerful explosions.

Reinhard
He finds his powers to be utterly absurd.

Trivia

 * He reveals that he is from another world to Tanya after discovering they are in a similar situation.
 * Aqua is able to deduce he is from earth as she sent people to other world before.