Not only are they unnecessarily sexualised, they are also extremely impractical in most cases. For instance, why would a female character with no superhuman durability to speak of go into battle with heavily armoured and massively powered opponents wearing what is essentially a bikini? It shouldn't happen, but it does happen in comic books - and it happens a lot. Of course, there are characters whose durability is such that they don't necessarily need to wear full body armour in battle but, even so, revealing 90% of their body is still unnecessary.
Call it the face that launched a thousand goth kids, imitators, and creepy Halloween costumes (not to mention a pro wrestler taking the look), but the grimy, almost commedia dell'arte inspired make up of the Crow is one of the most visually effective signature looks in film. Years of rehashes, reboots, attempts to redefine the look, and adoption by pro-wrestlers have made the Crow a bit played out, but when it comes down to it, that original look still flies.
The comic book version of Thor has never really been a sex symbol. Sure, he’s incredibly good looking, as the God of Thunder probably should be, but he’s never been viewed as sexier than, say, Wolverine. However, when Thor debuted on the big screen, anyone with eyes saw that Chris Hemsworth’s Thor is most definitely a sex symbol. It’s become so much of an issue that the recent Thor shorts directed by Taika Waititi even poked fun at Thor’s big muscly physique. His looks are so vital to the character that when fans saw his new look in “Thor: Ragnarok,” they obsessed over his haircut more than anything else.
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Witchblade first appeared in Top Cow Comics – an imprint of Image Comics – in 1995. Witchblade isn't actually a character in itself, so to speak - it's actually a sentient supernatural artifact, in the form of a gauntlet, which bonds to its (strictly) female host (the most well-known being NYPD homicide detective Sara Pezzini), providing said host with a variety of powers and a very skimpy costume (in essence, they become the Witchblade as a result).