He appears to be a cold-hearted character and careless about others. He does not like Kal-el.
It was later on revealed that he was a witness to the downfall of the Balesteros monarchy, and he recognizes Kal-el as the crown prince.
His mother was a concubine and when they were forced to leave the palace, he grew up to resenting Kal-el for having an easy life. That makes him Kal-el's half brother.