What happens to non-humans when magic leaves? Do they revert to normal humans or remain metas until they die? What about the IEs?

When the mana level drops enough, metas simply give birth to human kids.

IE's look human...although whether this is a magical spell or a natural effect is unknown.

It was a pretty impressive thing the SR writers did indeed - Two trolls can give birth to a human kid. At the same time, SURGE people retained their changes after the SURGE period ended. So hah again! The contrast? NONE! How do you like THAT?

Other then Spike Babies, you get nothing more than trolls wondering why they can't have a troll child, even if that somehow becomes a semi-constant.

I'd forgotten that about SURGE, thanks for reminding me. IIRC dwarves and elves can only be born that way, but with Goblinization, humans turned into Orks and Trolls. I would think that when the mana level dropped below what is needed to sustain them, Orks and Trolls would revert to human.

Yeah, in some sort of retro-goblinisation (normification?).

As I understood it, SURGE triggered damaged metagenes by way of a mana spike caused by Halley's Comet (who also opened a metaplanar bridge so the shedim could come, among other things). When triggered, though, these genes remained active ... they just needed a kick into theri damaged butt to start workingt, but didn't stop working when the kicking ended (kinda like an exothermal chemical reaction with a very high activation enthalpy will continue after being heated enough, even if you turn the burner off). That means SURGElings will remain with those who used them even after Halley's comet passed them by (though an eventual reversal, due to lack of sufficient mana levels, over the 2065-2070 period WOULD be a great, wonderful, splendid thing indeed!). Maybe they'll bring back Earthdawn's lizard people to compensate for the lack of funky pseudo-metas.

Kids...

SURGE victims are called "changelings," BTW. There's a nice bit in SoE about why that particular term wasn't exactly benign in some places.

Also, IIRC there is a reference that most events of goblinization have leveled out to almost none until SURGE struck.

Hermit, you might have a point except that in YotC it also states that Goblinization is a possible effect of SURGE, and since SURGE doesn't end when the mana spike from the comet does, its somewhat reasonable to compare Goblinization to the "Mana spike" of the world's mana level rising again - They'll remain, but they will not produce children of their own race.