Loki is one of the several powerful beings from the magical realm of Asgard, who have been worshiped as gods. Odin, once the ruler of the Asgardian gods, led his subjects in a war against their enemy, the frost giants from the land of Jotunheim (one of the nine worlds of Asgard). Laufey, king of the frost giants, was slain in battle and the giants were defeated. Surveying the spoils of war, the Asgardians discovered a small Asgardian god-sized baby hidden at the giants' main fortress. The infant was Loki, whom Laufey had kept hidden due to his shame over his son's diminutive size. Odin remembered his father Bor’s dying words to adopt the son of a father killed by his hands; Odin adopted Loki into his own family, raising Loki like a son along with his biological son, Thor.
Growing up, Loki had begun to notice the difference between him and Thor regarding Odin. It was favoritism between the two, and he couldn't fathom why. Being mischievous, Loki tried out many ways to get Odin's attention, causing mischief and doing a bunch of things, however, although treated like a son.. he knew his proper place. The thought formed hatred in his heart and motivated him to continue to put Odin and Thor in tough situations. As the years past, his playful mischief turned into evil schemes and plots, thus causing him to gain titles such as God of Mischief, or God of Evil and Lies. All of these evil doings drove Odin into cursing Loki onto a tree, in which he eventually escapes.
Over the centuries, Loki tries to seize Asgard and destroy Thor on many occasions. Odin, long-tolerant of Loki's attempts, magically imprisons him within a tree. Eventually freeing himself from this prison, Loki's hatred of his adopted family increases. After a moment of time, Loki made his very first big attempt on Midgard, starting with New York. However, his plan fell into ruins, when Thor found out where he was. After his acts, he was taken back to Asgard and served in prison for his wrong doings and the destruction he's caused on the humans planet. The trickster was then released, when Thor found that he needed his help in protecting Asgard. Helping Thor was a plan, but there is always another scheme within one, for he is the God of Mischief.