Yoshio Nakadai

Yoshio Nakadai was a ronin in the late nineteenth century who turned to a fierceful demon, The Heart of the Dragon.

History
In the late nineteenth century, He was a samurai who lived in Japan. Due to his swordmanship skill, combined with his bravery, earned him the title "Heart of the Dragon".

In 1859, He was tricked by a demon in disguise as a man named Cho, who is a messenger. He was sent to help a Father who is now deceased, and set up two marriages between his son and two other women. When Cho asked him to come along Yoshio agreed because he thought he was going to help the son decided which of the women he wanted to keep as his wife.

When they arrived, Yoshio and Cho. They talked to each of the wives, Keiko and the other Akemi. When the day was done and Yoshio was masturbating haah jk he was meditating in his room, one of the wives, Akemi came in and was crying.

He caught on to Akemi's game, called her out. She was demon who said she loured him down here because she had plans for him. (they weren't clear on what kind of plans; wanted to have that suspense) he disagreed. As she is disguised as the women, the demon comes at him to kill him because he refused to help her, he killed her and everyone said he was a murderer. Blamed him, and burned him in front of the whole town.

However, it was revealed, all of this was just a Demon plot to convert his soul to a "weapon of unimaginable power" in the hands of demonkind. His soul later converted into a fierce demon, The Heart of the Dragon

Supernatural: Heart of the Dragon
In 1969, a descendant of Yoshio Nakadai, Albert Chao (a Chinese-Japanese descent) invoking his spirit, now known as The Heart of the Dragon, but later banished by hunter Samuel Campbell and Jack Bartow, with cost of the latters life. In 1989, it came back again, and faced John Winchester, but it was able to escape again.

In 2009, Albert Chao later re-summoned him with the assistance of the witch Moondoggy Verlander with a powerful Demon Summoning spell. Unleashing him again to wreak havoc once more. But this time, Sam and Dean are able to dispatch him. Sam later administered a spell, releasing his spririt so he could move on, with addition sending back its demonic essence to Hell.