Seeing the fake Kabru gave me a good laugh, even more when the captain confused him with the real one, poor guy. It seems that the captain is unable to tell when he is tired or hungry, I guess that if he was the master of a dungeon his body kind of forgot about how to care of those needs (kinda like the people that the mad sorcerer made inmortal)
Also what exactly was the secret that Kabron wants to expose? I feel that it was already reveled, or most of it was but I don't remember in which chapter.
I think he refers to the ancient elf or dwarve technology of the dungeon, the series has said that everytime humans find ruins with those the elves always go and take it from them, treating all the races with sorth life-spans as children. At least, I think he refers to that.