He died when sealing Nine tailed demon fox inside naruto with "Dead demon consuming seal" which takes user soul as well.
In Malaysian mythology, a Hantu demon is an evil spirit which can possess animals or people. When the demon possesses an animal, it first kills that animals soul, then takes over its body. It has been known to drive people insane. There are many types of Hantu, including the Hantu Ribut, which is a storm demon, and the Hantu Kubor, which is a grave demon.
Demon's Crest happened in 1994.
Demon's Winter happened in 1988.
Demon's World happened in 1989.
Demon's Souls happened in 2009.
Demon Stalkers happened in 1987.
Demon Attack happened in 2600.
Demon Sword happened in 1989.
Give you soul to the demon.
he must have been born a demon from birth, he proably did not have a soul.
Humans can't kill a demon