WOJ please, whilst Jim can re-write his rules as he pleases but this hasn’t been shown in BG, all the immortals zapped by the Eye survived though I think only the Erl King was a genuine immortal not reliant upon a Mantle for his immortality.
What the Eye can do is break reality, little point being an immortal if reality has ended.
Relevant WOJ
"Is it even like dangerous to Uriel? Or his boss?
If Uriel just stood there in it, yeah, I mean he wouldn't, it could kill him I mean it's- again it's one of those- I mean Uriel is... he's so powerful that he's not even on the scale with everybody else. I mean yeah maybe the Eye of Balor could disintegrate Uriel if Uriel couldn't just immediately teleport anywhere or make the energy go somewhere else or basically do anything at all to defend himself. If he just stood there like a dummy, sure somebody could kill him with the Eye of Balor. He's not going to, freaking archangel."
As for Mantles I was kinda disappointed Hercules isn't around anymore, I've got a fanfic short story in my head of Thor and Hercules having a Bromance.
I do think that Hecate has some correlation with the Fae Queens. Molly's statue in Skin Game and Hades reference are too much groundwork laid for future appearance.