"Hadst relation" is a phrase that is quite specific in meaning and context, referring to a type of relationship in Old English literature. However, there are several synonyms that could convey a similar sentiment, including "family connection," "kinship," "blood tie," "ancestral bond," and "familial link." These alternatives highlight the idea of a shared history and heritage between individuals, emphasizing the importance of familial relationships in shaping one's identity and experiences. While "hadst relation" may be a niche phrase, there are many ways to express similar ideas using more commonly understood language.