Greg could be a great character to pair with Roderick. Their brotherly relationship has so much potential for interesting stories. They could go on adventures together or get into all kinds of trouble at home or in the neighborhood.
There might be a fanfiction where Roderick tries to teach Greg some cool tricks to be more popular in school. He could use his own experiences, both good and bad, to help Greg out. For example, he might show Greg how to dress in a more 'punk' style to stand out.
I don't know what the 'Gangdese Temptation of Ma Yuan' refers to. Can you provide more background information or context? This way, I can better answer your questions.
It's not a true story. 'Shepherd of the Hills' is a fictional work that might draw inspiration from various elements but is not based on real events or people.