It looks similar to Zygarde's face in Complete Form.
I do hope it is tied to it somehow. Zygarde and Gen 6 got shafted with the lack of a third game. They both share the same face, crown, zig-zag and hexagonal patterns and Paldea is literally connected to Kalos. The Zygarde movie and Short Film also shows it in a crater looking area.
Maybe the 3rd legend is a re'imagined' version of a Zygarde that was hit by the ultimate weapon like anon says
>>52939363 and they've retconned or finally decided to expand on it here.
I originally got Jörmungandr vibes (like Xerneas=Yggdrasil & Yveltal=Veðrfölnir/Hræsvelgr) from this pic rather than disk which could still work with Zygarde who seems to be Jörmungandr/Níðhöggr , but idk. Since Zygarde is the Order Pokemon maybe it's the opposite since it is changing Pokemon from their natural types.
Also, Zygarde's Aura Break is stupid powerful. Not only does it reverse both the Life and Death Pokemon's abilities, but it's unaffected by Mold Breaker, Teravolt, and Turboblaze, as well. There's some serious power behind Zygarde that Pokemon needs to address.
