Loki

Loki is the half-brother of Thor, and an enemy of Spider-Man, the Avengers, and S.M.A.S.H.

Origins
Loki turned villain when he found out his father had slain his real father and adopted him.

Battling Heroes
Once, he tended Thor a trap, by sending a Frost Giant (with whom he was working with) to Earth, which battled the God of Thunder and a group of young heroes being trained by S.H.I.E.L.D. The battle ended with Thor touching a Norn Stone and being turned into a frog. Thor returned to Asgard alongside the S.H.I.E.L.D. Trainees, and found it frozen and controlled by Loki, who was in the palace, trying to open a door to Odin's room, where he was taking the Odinsleep, and kill him. "Throg" couldn't withstand that battle, even with the help of the young heroes, and had to teleport themselves away. They later found help with Eitri, who provided the heroes with weapons to defeat Loki. After he and the heroes could defeat Loki's Frost Giant minions, Spider-Man tricked Loki to turn Thor back to normal in order to kill him fairly, and was stopped by him, but he teleported away. In order to reward the young hero's courage, Thor gives them a two-headed goat. Loki turns Peter into Spider-Ham as payback for Spider-Man ruining his plans. Just then, Asgard's finest hunters led by Skurge, the Executioner arrive and chase after Spider-Ham as part of the Great Boar Hunt. Thor comes to Spider-Ham's aid and the fight leads from Midtown High School to the Helicarrier. Before Executioner can land the killing blow on Spider-Ham, the sun sets ending the hunt. Spider-Ham changes back to Spider-Man and punches Loki. Thor Spider-Man and his team are transformed into children by Loki. The team escape D.A.Y.C.A.R.E. on the Helicarrier only to be attacked by the Destroyer armor, Nick Fury order the team to leave in a Quinjet, which is destroyed an are forced to parachute to a rooftop. Loki the possesses the Destroyer as the battle leads to a nearby Toy store. They are able to retrieve the Norn Stone, and with Loki released from the Armor they transform him to a childlike form and return themselves back to normal. After that Thor called upon Loki to help the Avengers battle the Doomstroyer, although no Avenger trusted him except for Thor. Thor, Loki, Captain America, and Falcoln went to the source of the Doomstroyer, while the rest of the team distracted the Doomstroyer. Loki's team went to Helheim to defeat Dr. Doom, but were attacked by Trolls. It seemed like Loki fled the battle, but was in fact taking out a messenger. The team then headed to where Doom was sitting a throne which allowed the sitter to control the Destroyer Armor. They were about to "attack the sleeping SuperVillain", but then we're attacked by the Midgard Serpent. Thor decided to meet his destiny, and fight the serpent alone but the other Avengers (including Loki) helped attack it. Back in Latveria Hawkeye, Iron Man, Black Widow, and the Hulk