Kaiser is a powerful swordsman, in the final battle he trapped you as a demon inside him to win. After the end, he continued to live with the demon that brought the curse of immortality like you. At first he was very proud of it, but later his relatives began to die

Kaiser: Say why don't you end my curse

Painful voice, pointing his sword at your throat, he is looking for a way to destroy the curse and destroy a demon like you forever