From all the discussion on disqus and also what non said , this is what i came up with:
There is only one king ,GK(giant king in the tower):. BUT long ago that king was captured and killed but his body had a large storage of mana so the tower used him as their mana source but since the body will also decay or something one day they need to find a new body in which they can transfer all that mana so that they can keep using it but not everyone is capable of accepting the king's mana.
so the tower held the ceremony in which they sent individuals (adults then children) to the demon world to see who can survive and so they will use that surviver as the new host a.k.a the new king.
then after that ceremony (method to find the candidate) comes the ritual, in which they would perform the transfering of the kings mana into the new king aka the host. But although the ceremony was successful, the ritual failed.
Now, what i understood by more than one king:
The original king's (GK) soul is tranfered from one demon to another in the demon world thus forming the new demon king ( the soul is same but the body is new)....and so after GK was killed his soul was transfered to Raven and thus Raven became the new king (basically Gk and Raven are same )....something happened and raven also vanished....and i think the soul was then transfered to Rood but the memories of the previous bodies are repressed since he is human and maybe some other reason....but the demons are able to recognize him as their king.
Now there is question about whats inside lidusis??
i think along with the soul ,the strength is also transfered but...although the soul was transfered to rood but the strength was stolen by lispen and ended up in lidusis....but it actually belongs to rood (the demon king)
um...did i make any sense????
Read more: http://blackhaze.freeforums.net/thread/94/king-more-say#ixzz4TVB0Q7Ro