Prince Heinel

The half-brother to the Gō brothers at their father's side. He was born the son of a traitor, bitter and more of the noble villain. As a child, he had a rough time being called a traitor's son, with no memory of his parents and only loved by his grandparents.

He wanted to clean the stain, but being a possible heir makes his second-degree uncle Zambajil hate him secretly and was hesitant to appoint him. Though first shown as a villain and using dirty tactics, he is later seen to be having noble qualities like playing fair at times in contrast to most of his comrades who prefer to use cheating methods like most super robot princes that would eventually succeed him.

(Source: Wiki)