It is no surprise the two beast kings helped the son of the human king. It is clear you eventually get rewarded for whatever action you take.
The Son of the King of Spain proved himself a king in action. His act of helping the two beast kings shows how large his heart is which is an important quality for a king who cares for the welfare of his people. Also, his courage and bravery to face whatever challenge presented to him on his path to achieve his goal. Finally, his perseverance and valiance in the battles he faced.
There is a lot to learn from the story of the Son of The King of Spain.
Thank you Vincent for sharing