Is Loki Satan

No. There is no one named Satan in Norse mythology. Loki's daughter Hel rules Hel, a realm of the same name.. Similar to "Hell" in various other religions.
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Helhiem (the proper name, meaning Home of Hel) was not similar to the Hell of other religions. It was not a fiery place of torment for the wicked. It was a place of rest, where most souls would go.
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RE:Helheim
Yes, yes when I was referring to "similar to Hell" I meant a place where dead people go.. In Icelandic Paganism, Hel is the abode of those who do not die a heroic death.. The alternative being Valhalla, ""similar"" to "heaven" in some religions, as it is an "alternative" to the "underworld". Though in some sources it is a hall like Valhalla, being an underworld merely influenced by Christian teachings. Again, in Icelandic Paganism it's proper name is Hel, which is also called Niflheimr/Niflheimur, but according to a number of people, Hel is in Niflheim, as they are separate places.
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This is a topic of much discussion, as there are some references to Hel being a part of Niflheim, others saying it is separate. I find that most practictioners of modern day Asatru, Icelandic paganism, hold that Helheim and Niflheim are separate.