This is where it gets a little confusing. Disney isn’t trying to trademark the character of Loki in Norse mythology. They couldn’t even if they wanted to, because Norse mythology is part of the public domain. That would be like Disney trying to trademark the Buddha.
However, Disney does already own the rights to Loki, the show, as well as their version of the character Loki, both in the Marvel comics and on screen. So while Disney cannot stop anyone from creating their own Loki artwork, they are well within their domain to put a stop to anyone profiting off their iteration of Loki.
This would include Loki’s “Low Key” shirt from the Marvel comic books, which is what the user was trying to sell. Despite this, YourBoswell’s most recent tweet claims that Redbubble has reinstated the product in his store.
Source : https://www.distractify.com/p/is-disney-trying-to-trademark-loki