Loki

Played by Tom Hiddleston

Loki is the Asgardian God of Mischief, a frost giant adopted and raised as Odin's son and Thor's brother, gifted in sorcery, illusion, and shapeshifting. Driven for years by resentment over his parentage and place in the succession, he has alternated between villain and reluctant ally, invading Earth with the Chitauri, faking his own death multiple times, and eventually being pulled into the Time Variance Authority's bureaucracy after stealing the Tesseract. Read more →

First turns up in Thor.