The origins of Aniva,true ice and black ice

So yeah originally made a bigger intro post,but that got lost when I failed to create the discussion thanks to the boards switching regions for no reason -.-

Anyway I've recently thought a bit about the whole freljord stuff a bit,in particular where Anivia,the true ice and the black ice are coming from,so here is my theory: True ice So yeah we don't know where the true ice comes from.I've read on the wiki that anivia was actually the one who froze gnar in true ice(the source there links to a reddit post,which links to a spanish riot post,I dunno how accurate this is),this suggests that anivia has some control over true ice,I could imagine her even being made of true ice(since it is hard for me to believe that she would melt in warmer places).But does that mean she is the source of it?I mean if she were,then shouldn't she be able to supply the avarosans with true ice?Now she could have forgotten this ability thanks to her loosing parts of her memories when she resurrects,but that sounds a bit like a lame excuse to me. So I suppose that the watchers are the original source of the true ice(or maybe the ice born but they were created by the watchers,so the watchers remain the original source)and that anivias use of the true ice is limited.

Anivias origin So Anivia is a one of a kind creature,which raises the question where she comes from.Originally I thought she might be a primordial force like brand,but it seemed rather odd that she is solely linked to the freljord.Also if Anivia is connected to the true ice(or made of it) and the watchers were the original creators of it,wouldn't that mean that the watchers were the ones who created anivia?It would certainly explain why anivia is instinctively protecting the freljord and why she has some power over true ice,as the watchers might have created her as an eternal guardian for their home.

The black ice However as we know the black ice would corrupt anivia if it corrupts the freljord too much,but where does it come from?I mean if it was created by the watchers then it shouldn't have been a problem for them to corrupt the freljord enough to corrupt anivia,but the fact that anivia fought alongside the avarosans suggests that it never came to that. So I suppose that while the black ice was created to corrupt anivia(I mean i see no other reason to use it over anything else if the watchers never had a reason to corrupt the land during their regin),which would make her more amoral so it'd be possible to turn her into a powerful ally,the watchers created it either too late or Lissandra herself created it after the fall of the watchers to corrupt her.