Tai Ishii

Once upon a time, a man killed the king's pet dog. He was executed and reincarnated as a canis but with the memory of his past life as a man.

A man is walking along the beach. Then a demon, the man’s pain, appears and chases him. The pain is unbearable, coursing through his entire body. He somehow manages to get away, but eventually, he returns to the ocean even though he knows that the demon will appear again if he goes there.