Loki Laufeyson

Prince Loki Laufeyson-Odinson is the main antagonist of Thor and the tritagonist of Thor: The Dark World and deuteragonist of the Thor trilogy as a whole. Loki was the younger, adoptive brother of Thor and Hela, the adoptive son and youngest child of Odin and Frigga and the only biological son and child of Laufey

Early Life
Loki was born on the planet, Jotun to his father, Laufey in 946 A. D. However, Loki was very small for a Frost Giant and left to die in a temple. However, he was soon rescued by Odin, the archenemy of Loki's biological father. Odin later altered Loki's appearance, changing his bluish grey skin and red eyes to pale skin color with green eyes. His wife, Frigga, willingly became Loki's adoptive mother and the couple raised Loki together, alongside their biological son, Thor.

Trivia

 * Despite being frost Giant, Loki has no respect for his heritage, and called them monsters.
 * He is mostly referred to as an Asgardian due to being raised in Asgard all his life.
 * Loki's relationship with Thor is similar to Nebula's with her older sister Gamora
 * As a child, Loki disguised himself as his brother's favorite animal, a snake and often transformed back into his normal self, shouting "surprise" and later ends up stabbing Thor in the chest.
 * Hela telling Loki and Thor to kneel is a callback to Loki, when he yelled at the Midgardians to kneel before him.
 * One of Thor's schemes while escaping Sakaar was called "Get help," where Loki pretends to be injured and Thor calls for people to help his brother who is "dying" before throwing Loki at the people they atry to knock out. According to Loki, it is quite humiliating, but amusing to Thor. Even when they area bout to fight Hela, he tells Thor he is not doing the "get help" scheme again.

Quotes
"You're not seriously thinking of going back, are you? Our sister destroyed your hammer like a piece of glass. She's stronger than both of us, she's stronger than you; you don't stand a chance! Do you understand what I'm saying to you?"

- Loki to Thor, referring Hela

"Last time we saw you, you were trying to kill everyone. What are you up to these days?" "It varies from moment to moment.""

- Bruce and Loki