Step-by-step explanation:
His entire life he was denied of knowing his origin due to the fact he was going to kill his father in cold blood and marry his mother. Even though he achieved being the king of Thebes by nobly defeating Sfinga, the incest that occurred is so much more humiliating. After he had 4 children, no support sistem for power lacked there. When all his sins were found out, his mother and two sons killed themselves. It was a tragedy for the wrong he committed. Due to all of the bad his life was about, his life was at the end taken by the mythical creatures. His daughter Anthigona was by his side the last years of his life, and so to have someone with him after all he committed and his life being taken nobly, was actually what made it heroic.