Kuzan has broken the link that was holding him to the throne!
He himself exactly knew that he is holding Xue Ren and probed him to conquer and devour more women, hoping that he will somehow get more familiar with nature attributes this way... However, in the end, he just had to accept.
'My whole past will be given to him.'
The past where he struggled and learnt more about others... The past where he had began looking down on others simply because their nature attributes were weaker than his, a human!
'You have 'fire' in your race, so tell me, why is your fire like shit compared to mine?'
'Without those wings, you would look more human like... Maybe then... your wind attribute would be as good as mine... as human's...'
'Cyclops? Earth's beloved children? How about I take care of that shitty eye of yours to make you more human like?'