I am sorry why are they attacking him?

kurak didn't follow the contract he promised to devourer by teaming up with hexabel

I mean the devoured didn’t by any means for at Kursk to form an alliance with Hexabel( I don’t remember how to write her name) so he came out to talk with hexabel, but isn’t she free to do what she want? And if indeed some contract was broken, it is not on Kurak’s part, but Hexabel, so he should be taking it out with her, why kill him?

So if i understood the last chapter correctly they're attacking both 'cause they're plotting on getting something important without the primordial core knowing, so i believe it has something to do or with devourer itself or with the dungeon they're protecting.
They say the name and show how it looks like but we readers don't really know what this is.