The story that I have heard about Loki is this - He was the god of mischief but started a rebellion in heaven, trying to take over. He lost and was banished from heaven. He then became the god of evil, and pretty much is now Satan. Now thats cool!

Loki is the Norse God of trickery, mischief, and change; a major character in Norse Mythology. Blood-brother of Odin and traveling companion and friend of Thor; his wife’s name is Sigyn, his children’s names are Hel, Fenris, Jormungandr, Vali, Narfi and Sleipnir. Loki is pleasing and handsome in appearance according to the Eddas. He is renown for his cleverness and for helping the Gods out after he has gotten them into trouble as well as his great ability to make them laugh and cheer them up.

He has domain over fire, and is a master magician, conjurer as well as shape-shifter (In some cases changing gender). Loki is bisexual, having sexual relations with both male and female in mythology. Bearing in mind Loki’s dark side as well as his good one, he is most valuable as a witty, entertaining friend, and a God to call upon.

Loki is not an evil malevolent being or the Norse version of Satan or some fallen angel. The later influence of Christianity on Norse culture resulted in changing the mythology portraying Loki as evil incarnate. This is not uncommon, Christianity often demonizes other ...

Loki is the best god in all of the pantheons. It's a fact.

Loki is the Norse Trickster god (originally a Jotun till he became Odin Allfather's blood-brother).
He plays some part in Ragnarok, the end of the world in Viking myth. For this reason he is often interpreted as a Satan figure.
Also, the only reason anyone knows any Norse myths is because of the Eddas, two writings on them. One was by Snorri Sturulson, and that writing is deeply influenced by Christianity. In Pagan beliefs, the end of the world is often seen as one being followed by renewal; it was seen differently by the pagans, and so Christian interpretation is, alas, inherently wrong.
Most Wiccans and other modern-day Pagans choose not to pray to Loki. He is the god of change, often change that is very necessary, hard to get through, and unwelcome at the time. Usually Loki's lessons are full of mischief, but the overall meaning is good-natured and helpful.
Loki is also, from a different perspective, a distinctly fey god. While the other Norse gods were all unchanging and fixed, as pagan gods usually are...

The Norse God of mischief. Also the villain in the movie "The Avengers" played by Tom Hiddleson that has completely taken over Tumblr as a whole and has turned previous fangirls of other media into Loki-serving mindless slaves.

Also another word for "troll" due to said event.

Loki, Vamm Goda, The disgrace of the god's, but also Thor's Runi. (Thor's friend.)

Mischeivious, but not malicious, Loki enjoyed playing tricks on the Aesir, and pretty much everyone else, and toying with the sanity of everyone else around him...

Also, the eternally clever Loki was always using those around him for his own means...

There are a lot of untrue statements here, so I might as well clear things up a bit.
Loki is a major character of Norse Mythology. He is often referred to as the trickster god, but he's technically a giant, son of the giant Farbauti. And despite previous definitions, he is NOT related to fire, that's a common misconception because the name Loki is similar to another name meaning fire.
Through the giantess Angrboda, He is the father of the half-dead woman Hel, the wolf Fenrir, and the world serpent Jormungand. He also once shapeshifted into a mare and gave birth to the eight-legged Sleipnir, which became Odin's favorite horse.
Loki is described as being handsome in appearance, but clever and deceitful. What makes Loki a truly fascinating character are his dynamic and unpredictable actions. Without the exciting, unstable, flawed Loki, the Norse Myths wouldn't have nearly as many interesting tales as they do today.
Loki often causes trouble for the gods. However, what's interesting is that it's often also Loki's cunning that gets them out of these messes. Many times, probably for the sake of fun, Loki helps out the gods while they are in tough situations. But at the end of the world, Ragnarok, Loki's true allegiance is tested, and he betrays the gods by fighting against them alongside the giants. At Ragnarok, he encounters the god Heimdall, and the two kill eachother.

the main villian in the thor comic series who with out which the sereis will wither and die as it has on many occastions