... Lame title, but anyway, you can probably guess what this question is about.
In book 4, it showed us a new creature called a Groul, strange and ghastly creatures that live in the dark caverns of Cielis that used to do guard work for the Council a long time ago.
My question is where did they come from and why do they resemble elves?
My theory is is that they were once elves, but under some sort of disease outbreak or corruption, they became what they are now. Of course, there isn't any proof of that and they could have simply just been a design coincidence, but you also can't deny the possibility either since everything isn't always sunshine and butterflies, but the idea is indeed probably too dark for a children's graphic novel.