"I was not someone who participated in other people's castles"

This quote by Stephan Jenkins is likely referring to the concept of living in someone else's dream or fantasy. He is saying that he was not somebody who was content to simply accompany what others wanted or anticipated of him. Instead, he was identified to develop his own course and live his own life. He was not going to settle for another person's concept of success or joy. He wanted to make his own choices and produce his own fate. He was not content to simply follow the crowd and be a part of another person's vision. He wished to be the architect of his own life and develop his own castles. He wished to be the one in control of his own destiny and not belong of another person's.