Initiated a battle with this Abeix guy and I could not seem to cast any direct damage spells on him, I always got the "tile is blocked message" while trying to target him.

I had similar issues with my melee guys, most of the time it would say "tile is blocked", I was able to hit him once and am not sure how, maybe there is only one tile you can actually melee him at a time. This might have something to do with the fact that he's in that big crack in the ground. Maybe it's by design?

I was able to hit him repeatedly with the Storm spell (I think it's called Storm, the one that hits a random enemy) because it's not a direct damage spell and since he's the only creature on the board he always gets hit by it.

As a side note, I thought once I killed this guy I would be able to settle in his territory but after his death it still has it's borders and I cannot settle there.