When I was questing in empyrea the Bat and the Scropin talked about a place called "The Shadow Realm". What is that place?
No-one really know, I guess it's up to speculation. Hmm... I speculate that the Shadow Realm is a pocket dimension created by Shadow Magic, where only beings tainted by Shadow can go. If we ever go there, we will be greeted by the greatest and most terrible things Shadow Magic has to offer - and I doubt they would make us feel welcome.
Where you get sent when you lose a card game in 4Kids dubs instead of the afterlife to keep everything G-rated . Seriously though, haven't got to the point where they talk about it myself, but it's probably your standard "anti-realm" that must exist as the equal and opposite of the Spiral and Spider's "true home" or some such (there's no way we saw more than a fraction of what he could do in Mirage). Or possibly the realm that the primordial goo that became the First World came from, which might make more sense looking at some of the lines from the description of Shadow Magic:"it is an underlying, reality-defining and bending magic" ... "Shadow magic was forbidden for it touches the true essence of the Spiral."
Our good friend The Curator actually answered this, this is what he had to say
Rat and Scorpion went to the the Shadow Realm. Where's that? Well, that's a bit of a mystery. But Spider had to have someplace out of Raven's sight where he could hide from her wrath, what with his weakened condition and all. The Shadow Realm is that place. We may deal with it more later, but I'm content to wait.