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.
"You just got Loki'd."
"He's just Loki'ing, ignore him."
"That guy is such a Loki."
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!
The angel of death. God's sword-arm. He was responsible for the flood that lasted 40 days and nights, the destruction of Soddom and Gohmorrah, and several other things.
Also my long-time name online. Anyone with the name of Loki thats a moron is NOT me, but an imposter.