Ah, sorry i checked it in google because my memory is sooo bad, but actually Ishtar is goddess of war and seggsual love (Ereshkigal is the underwold ones, i confused them). But either way she is, Ishtar's myth also not good in irl myth xD
Meanwhile i never heard Irkalla. Well then again, the goddesses in this manhwa should be inspired, not reflecting irl myths.
It's Mesopotamian myth. In the myth, Ishtar and Ereshkigal (Irkalla) are sisters. Ishtar = War + sexual love, Ereshkigal (Irkalla) = underworld. In the great history of Gilgamesh, Ishtar isn't that good of a goddess, thats why whether it's Ishtar or Irkalla never settled right in my mind as a good one.
Btw if you wanted to search the myth, be careful that you might accidentally read FGO storyline. They do take reference of histories and myths, but they also changed it for audience and entertainment in game. Though also the reason i was a nerd of myth back then ╮( ̄▽ ̄)╭
Hey, no wonder i feel familiar by the goddess name. Though, i know it's only INSPIRED, so no need to take it seriously. I just feel the irony. The good side worships Ishtar goddess of life, but in irl of myth, Ishtar is the goddess of underworld cmiiw ww