Loki

Finally, here's my vision of Loki (or Loge in Richard Wagner's "The Ring of the Nibelung"), the famous Norse "god" of malice, discord and trickery ! Although the son of two jötnar called Farbauti and Laufey, he was adopted by the Aesir after he and Odin performed a blood pact (as reported in stanza 9 of the Eddic poem "Lokasenna"), befriended Thor, and married the goddess Sigyn. This jötunn, with an intelligence surpassing that of all gods except Mimir (the god of wisdom and hidden knowledge), shapeshifting powers and the ability to run in the air, is renowned for his ambivalence. Clever but impulsive, cunning but irresponsible, Loki does not allow himself to be grasped.
With the jötunn Angrboda, his second wife, he had three monstrous children : the giant wolf Fenrir, the sea serpent Jörmungand, and Hel, the keeper of the non-heroic dead's dwelling. Odin, having heard of their fatal role in the Ragnarök, banished all three of them from Asgard, unaware that by doing so, he was allowing the prophecy to come true...

Several times he had adventures with Thor, especially in Jötunheim, and he put him in sometimes perilous situations, although in general the latter got out without too much difficulty, for example with the giant called Geirröd, who had captured Loki as he changed into a hawk.
When the jötunn Thrym stole Thor's hammer and asked for Freyja's hand in return, it was Loki who acted as the messenger between the two parties. Naturally, the goddess refused, but Heimdall suggested sending a disguised Thor instead, which greatly amused Loki, who accompanied his embarrassed sidekick, turned into a maid. If Thor's behavior during the wedding feast aroused Thrym's suspicion somewhat, Loki undeceived him each time, and when the giant returned the hammer, the god of thunder seized it, and slaughtered his host as well as all his family.
In chapter 42 of Gylfaginning (first part of Snorri's Edda), a master builder hiding his identity as jötunn proposed to the Aesir to build them a fortress to protect them from the giants, and this in a year and a half. Once again, the goddess Freyja was demanded in payment, along with the sun and the moon, at least if he kept his promise. But the gods agreed, believing that this stranger could never complete his work in time. When they saw how much the horse Svadilfari made the builder's job easier, they ordered Loki to slow him down by any means. Thereupon, the latter changed into a mare to distract the stallion. The jötunn, realizing his horse was too busy frolicking, grew angry and revealed his true nature, before being struck down by Thor. The fruit of this union was the eight-legged horse Sleipnir, which was very well received by the Ases, becoming the mount of Odin.
Loki also rescued the goddess Idunn when she was kidnapped by the giant Thjazi, although the kidnapping was only possible thanks to Loki, who had himself been captured by Thjazi before. As for the dvergar Andvari's cursed Ring, he probably would never have harmed anyone if Loki hadn't gotten involved ...

If the pranks of the god of mischief had so far had little impact, which he also tended to repair himself, the episode of Baldr's death (described in chapter 49 of the Gylfaginning) marks a turning point in the development of Loki's character.
Worried about her son Baldr, the goddess Frigg made every element swear never to harm her son, which made him practically invulnerable. The gods then honored him by throwing objects at him that did not hurt him, which irritated the Loki. But the jötunn learned that Frigg had not bothered to make mistletoe take this oath, since she considered it harmless. Loki then made an arrow from a twig of mistletoe, and handed it to Höd, the blind archer, urging him to shoot a projectile at Baldr, his brother. Before the assembly, Baldr was stabbed and collapsed, dead.
But Baldr was the son of Odin, and, for the Allfather and the other gods, it was the last straw that broke the camel's back. Hunted like an animal, Loki was taken to a cave, and tied up with the entrails of one of the sons he had with the goddess Sigyn. A snake let its venom trickle down the traitor's face, but Sigyn, loyal to the end, held a bowl over his head. However, every time she had to empty the container, the venom would trickle down Loki's face, who was writhing in such pain that it caused tremors.
It will be so until Ragnarök, where the Aesir will lead their last battle against the jötnar and their allies. Loki will free himself, and wishing for revenge, will side with the giants and his three monstrous children, once banished by the gods. Fenrir will devour Odin before being killed by Vidarr, Jörmungand and Thor will kill each other, and Hel shall lead an army of dead. Meanwhile, Loki will face off against Heimdall, but none of them will survive...