Complex sentence: Bhattarai is regarded as one of the high caste in Hindu religion, since the descendant of this sub group is directly related to a saptarishi, Rishi Vasisht.
Split into simpler sentences: Bhattarai is regarded as one of the high caste in Hindu religion. Since the descendant of this sub group is directly related to one of the saptarishis i.e., Rishi Vasisht.