二十年前,广寒门主与她师祖清广真人一同杀过一个大妖怪 I need help with these two people's name/titles. Is it Lord Guang Han Men and her master's mentor, Zhenren Qing Guang? I know 真人 is some sort of title, but I don't know how to translate that (maybe spiritual master?), and I'm not sure what 师祖 is either.
This is my guess: 广寒门主 Master of the humble Guang Family 她师祖清广真人 Her teacher's ancestor, the Daoist Qing Guang 真人: 指古代道家洞悉宇宙和人生本原,真真正正觉醒,觉悟的人称之为真人。 Basically, it is a title for Daoists (or Taoists)
Yeah, 真人 is a Daoist title for a perfected, enlightened, or self-actualized person. Translating it simply as "Daoist master" would be fine. 师祖 is a "Martial Ancestor" or "Ancestral Master". It refers to someone who is two or (potentially many) more generations higher in seniority. So it could be her master's master in this case, or it could even be her master's master's master (etc, etc).
I would go with... 广寒门主 = Master of the Guang Han Sect 她师祖清广真人 = Her grandmaster, the Enlightened Qing Guang. 门 refers to a sect, not a family.