Yuyutsu in the Mahabharata was the son of Dhritarashtra and a maid. He was born during Gandhari’s extended pregnancy. The name of the maid is not mentioned in the scriptures. Some later texts give the name as Vishakha, she was the eldest maid servant of Gandhari. The name of Yuyutsu's wife was Bhadra.
Kauravas, the 100 sons of Dhritarashtra and Gandhari, considered him inferior and therefore Yuyutsu did not get the respect of a prince. Duryodhana, who was always insecure, saw him as a threat to his throne; just as he considered the Pandavas as a threat.
The character of Yuyutsu was different from the Kauravas. He stood for Dharma and questioned the unethical practices of Duryodhana and his other brothers.
He argued against Draupadi being staked in the game of dices and disrobed in the Hastinapura court.
When it was time for the Mahabharata war, he gave primacy to Dharma and crossed over to the Pandava side.
He was an important and key member in the Pandava side during the Kurukshetra war. He was given the charge of supplying arms and other necessary items to all the warriors and soldiers on the side of the Pandavas.
He was the only Kaurava who was not killed in the Mahabharata war.
After the war, he became a key member in the court of King Yudhishtir.
When the Pandavas decided to take Vanvas by giving away the throne of Hastinapura to Parikshit, Yuyutsu was appointed as his key advisor.