Quote Originally Posted by WonderScott View Post

I wouldn't sacrifice her human aspect for being a Titan or Jotun because it loses her human foibles. Also, it'll make it more interesting if/when she encounters other giants of myth - she's like them, but not of them. That situation can provide some interesting conflict.
I would simply write around that in a Loki kind of way. Like what if during the Titanomancy or during the last great purge of Jotuns on Earth, Giganta was sufficiently small and scawny that she managed to hide from the gods and has since spent the ages living among humans, but kept what she is quiet out of fear of the gods returning for her.

By the time we reach the modern era, Giganta has like much of humanity woken up to the idea that the gods are either dead or pays no more attention to Earth, and she loosens up a bit. And she manages to still keep it low key, but improves her lot through her powers for a few decades, but then Diana shows up and the Gods follow in her wake. Giganta has now grown a fondness for her new way of life, and refuses to be put under once more and reasons that if the gods have been there all along, then they clearly don't care that she's around.

Whenever or not you want to tie her to any mythological giants largely depends on if you want her to have any additional powers other than her bigness, which I have to say, she should.
So picture this. Giganta looks like a normal woman at most times, though I think her 'small' size should still be Big Barda-tall and quite heavy-set like she's a weight lifter. But when she grows a hundred feet she can't look human any longer and she takes on the appearance somewhat similar to the GoT White Walkers and the Night King, not necessarily making her look like a frozen zombie, but more like she's made of an ancient block of ice underneath and what passes for her skin looks more like dirt thats been frozen onto her.
The effects of her transforming into her real form could also have an effect on the area, like the act of her doing so cause the temperature to plummet and a blizzard starts covering the area in snow and ice. In the past, she's used this trick simply to get away from potential dangers, and in the modern age it's shown that she can actually move fast enough that people think her storms are odd but natural.
Plus you can give her other ice-related powers, like generating coldfields, throwing icicles, regenerate by coming into contact with water.

Anyways this is just a suggestion you could use, but it might be going too far off track that maybe we are talking about a new character.