Lart had a pretty good character development, he is becoming more distinct from his sister --- who, on the other hand, is devolving more and more into a greedy, scheming snake with malicious intent.
If he is given enough guidance, I think he can become a benevolent ruler.
I forgot if Blondina herself aims to be an empress... but I think she can still hold the same amount of power and influence if she chooses to be with the divine beasts, as Amon's partner.

Just some unpopular opinion: I really want Blondina to support Lart in becoming an emperor though. He changed so much from the time since they were kids. And look at him getting all motivated to gain power just so he could be with his love.