Yeah it literally seemed like time-traveled Annie with Piwi after Helck goes Rogue and she's back to prevent it from first place.

Interesting idea! I have really enjoyed the slow, unspoken worldbuilding in this show so far. We see ruins that hint at a civilization mysteriously wiped out in antiquity, some vague, super dangerous threat to the north of the demon territory, some unexplained toxin permeating demon lands. All of this hints at deeper lore and a fleshed out world, but the story doesn't give us some huge exposition dump explaining things. It reminds me a ton of how Adventure Time very slowly builds its world over the course of many seasons, but still never really explains things, content to leave some questions unanswered or open to interpretation.