small size. Odin took the child, out of a combination of pity, to appease the memory of his father, and because he was the child of a worthy adversary slain in honorable combat, and raised as his own alongside his biological son Thor. Throughout his childhood and into adolescence, Loki was resentful of the differences between how Thor and himself were treated by the citizens of Asgard. The Asgardians valued great strength, tenacity, and bravery in battle above all things, and Loki was clearly inferior to his brother Thor in those areas. What he lacked in size and strength, however, he made up for in power and skill, particularly as a sorcerer. As Loki grew to adulthood, his natural talent for causing mischief would make itself manifest and earned him a nickname as the "God of Mischief"; his mischievousness eventually became malice as his hunger for power and revenge grew stronger. Several times he tried to use tricks to get rid of Thor, such as telling him to guard a hole in the wall that he himself had made. In time, his reputation grew from being a playful and mischievous trickster to the "God of Evil". Over the centuries, Loki attempted on many occasions to seize the rulership of Asgard and to destroy Thor, even helping the Storm Giant Ghan to escape Thor planning to get a debt from him later, and aided other enemies of Asgard, planning to take over. Odin, who had grown weary of Loki's mischief, magically imprisoned him within a tree until someone would shed a tear for his plight. Loki eventually freed himself by causing a leaf to strike Heimdall, the guardian of Bifrost, in the eye, which made him shed a tear. Loki compiled an extensive criminal record in Asgard, and was frequently exiled. He later met the Sorcerer Eldred, who taught him black magic, repaying Eldred by later giving him to the Fire demon Surtur. Battles with Earth's heroes Loki's schemes eventually came to include Earth itself, and often fought with Earth's superhuman heroes to take their planet, and often Asgard itself. He first battled Thor on Earth in modern times after escaping from the tree; Loki then manipulated the Hulk into wreaking havoc using an illusion of dynamite on train tracks, while in astral form in an attempt to lure Thor to Earth, which inadvertently led to the formation of the Avengers