Board Thread:General Discussion/@comment-27364001-20160228034454/@comment-25926288-20160228112418

Lol, Nicky, totally bring down the house with those spoilers. (I don't know if the OP wanted spoilers as this thread wasn't in  the spoiler section).

Anyhow, since it is now, carry on.

My theory is that they have a set time in the Underworld lest they degrade into spirits (or whatever the things the others are. I think if you die, you either stay or go straight to "beyond the afterlife". Also, i'm not too sure, Hades is too keen on magic being used in the Underworld, either. (I sort of think like in Kingdom Hearts where "heroes are zeroes" and your full potential is limited).

I'm sure Emma will revive Killain with Deus ex machina....or the magoical macguffin of the episode right before or during.

And lastly, the Underbrooke is only a small portion of the Underworld as Hades has billions of souls in the Underworld.