Norse mythology is weirdly the most diverse part of the Marvel Cinematic Universe

Marvel Studios announced a host of casting news for the upcoming film "Thor: Ragnarok" last week, revealing that Cate Blanchett, Jeff Goldblum, and Karl Urban were joining the film.

They also confirmed that Tessa Thompson, who starred in "Creed" and "Selma," would be playing the Asgardian heroine Valkyrie.

Her casting adds a welcome bit of much-needed diversity in the Marvel Cinematic Universe, but in some ways it only highlights the studio's other problems with whitewashing.

The heroes from the Thor comics are based on Norse mythology, and in the books almost all of them were originally white. This is partially because comics historically have a problem with diversity, but also because, you know, they're a bunch of Viking gods, so it made a certain amount of sense.

In the movies, however, Idris Elba was cast as the traditionally white Heimdall, and Thompson is now going to play the fair blonde Valkyrie.

Norse mythology seems like the one area where Marvel could've maybe been given a pass when it comes to diversity, and it's great to see they've instead chosen to cast black actors to play these characters. It also makes it even more mystifying that they're casting white men for characters that should by all rights really be of Asian descent.

The studio raised eyebrows when they cast "Sherlock's" Benedict Cumberbatch as Dr. Strange, a traditionally white character who is seeped in Asian tradition and mysticism. The comics-accurate casting might've merely be a missed opportunity to not have a white male lead for the 14th movie in a row, but they also cast Tilda Swinton as the Ancient One, a powerful sorcerer of Tibetan descent. This blatant whitewashing earned Marvel a well-deserved round of criticism. "Doctor Strange" co-writer C. Robert Cargill blamed political issues with China for the race swap, not that it makes it any better.

Marvel also botched an opportunity to diversify with their upcoming Netflix series "Iron Fist." The character is white in the comics, but has been criticized for being an outdated "orientalist-white-man-yellow-fever narrative." Instead of updating the character with an Asian actor, they instead cast Finn Jones, best known for playing Ser Loras Tyrell in "Game of Thrones."

It's somewhat maddening that a cast of characters directly based off of Scandinavian gods is more open to diversity than characters with roots in Asian history and culture. If her past work is anything to go off of, Tessa Thompson is going to be a terrific Valkyrie, and it's nice that Marvel didn't arbitrarily limit themselves to a white actor. Maybe by the time we get to Phase Four that ethos will be true for heroes on Earth and not just Asgard.