> They made saber as their own king Arthur, they didn't just say oh no thor cant be thor because batman made him doubt himself, they can have succession alright with Jane being the next goddess of thunder or whatever, why just try and change core parts of a character, would it feel right if spiderman didn't have uncle Ben dying (or aunt may alternatively) or batman didn't lose his parents.
> The Tony stark giving title of ironman to Riri(?) Is ok, it not like she basically steal his name (tony).
> (Basing on comics where takes thors name, the riri succession types are alright if they make the character original.)
> _The fate series makes good use of it where saber thinks she's was unworthy because she failed._
The Thor in Marvel isn't the actual mythological Thor either, but some space aliens that for some reason fashion themselves after Nordic myths.
Also a character's gender is rarely ever a core part of their character that you can't do without.
Not to mention unlike Thor in Marvel who is just some alien also called Thor, King Author in Fate is still remembered in the modern time as male in their own universe, but only when summoned that their Master realise their actual sex and gender; the same for just about all of the genderbent characters introduced in Fate barring the ones who are specifically mentioned as coming from a parallel dimension/timeline.
In fact, King Author's set up in Fate was done so PRECISELY because the identity of male is extremely important in ancient times so she made sure that she would be recognised and remembered as a man instead. That is a clear change of a core part of King Author's myth by directly challenging it.
So King Author in Fate is okay, and Lady Thor isn't? Let me guess, you aren't actually looking for the "change core parts of a character", are you?
Also, I'm rather puzzled about your very last line. I'll read it as being rather insignificant but it seems to carry the implication that Fate's King Author is good because she failed (which she actually didn't, she got owned by her tragic fate, the namesake of the franchise, as is the case with most introduced mythical or historical character).
Come at me, mods.