There's a theory that Loki is associated from early nature myths with wildfire, from the fact that he is born of Fárbauti and Laufey. The name of Fárbauti, his father, means "dangerous striker" which could well mean lightning (or just warrior). The name of Laufey, his mother, means "leaves", and her other name, Nál, means "pine needles".
From what I understand, the association of Loki with fire is up for debate, especially as in the myths he fought fire personified, Logi, and lost; the association could possibly be a later Christian "Satanic" syncretisation/influence.
This is a good example of Loki interpreted/understood/simplified (for children) as an evil, fiery Satan-figure:
"New Trickster In Town" - The Life and Times of Juniper Lee (2005)
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