Scion Speculation

I guess should've said MO for the Scion offering to help.   Regardless, I don't see Spite coming back bottom line.  His story has played out. 

My guess for the scion in Scion's Aid is Vanessa Long.

You know... the Scion believes they can swoop in and replace OblivAeon whenhe is defeated. Steal all his power... but then what will happen to the other Scions? How closely tied to OblivAeon's existance do we think they are?

Tough to say.  It also depends on whether the Scion providing aid is willing to share.  It could be "all the other Scions whither and die" is a desired outcome.

Do we know what happened to grandpa legacy after he appeared during the shattered timelines event? What the Scion says is implied to be sinister, but never said outright to be. Since the narration reads as third person omniscient limited it could be that sinister element is result of the heroes having been embroiled in devasting battles continuously since the appearance Progeny. Maybe it’s grandpa legacy.

The Scion talks like kind of a condescending jerk, though, I don't see that as fitting any Legacy.