I do find it wild that despite not being the protagonist, Marvel!Loki was technically created earlier than Marvel!Thor in 1949. This was for Timely Comics (which became Marvel Comics) in a comic aimed towards girls where Venus was the protagonist.
He was designed as a ginger with lots of Satan-like/Hades-like aesthetics at the time (both Marvel!Thor and Marvel!Loki were gingers at first).
Loki as we know him now with the green-gold color scheme and black hair, did appear after Thor in JiM #85 (1962).
There was also a brief time very early where Mjolnir didn't turn Donald Blake into Thor, but Donald Blake just gained Thor's powers while wielding Mjolnir.













