What is the relationship between Tan Erlang's father and Yuan Yi in Blade to Destroy the Soul?

Blade to Destroy the Soul is not directly related to Tanjiro's father and Yuan Yi.

Guo Yuanyi, a friend of Tanmen Tanzhe Temple, the ancestor of Tan Erlang's father, returned to the place where he once lived with Shi after being expelled from the ghost squad. He met Tanmen Tanzhe Temple, where he was attacked by ghosts and Su Yezi, who was about to give birth, and saved the Zaomen couple.

Because there were no children after the country, I gave my breathing method and earrings to my family in the kitchen door. Yuan Yi realized in the Zaomen couple what she could not do for his wife and children, and she was saved.

Role introduction:

Yuan Yi was born into a samurai family during the Warring States Period. After leaving home, they lived with a woman named Shi, and later they got married. After his wife and baby were killed by ghosts, Yuan Yi joined the ghost killing team and taught the breathing method to the members of the ghost killing team, which greatly improved the strength of the ghost killing team.

However, Yuan Yi was later expelled from the Ghost Dance Team because Yuan Yi failed to kill the Ghost Dance, leaving the ghost bead world around Wu Bei at large, and his rebellious brother Yan Sheng killed the master at that time.