What are Shinigami?

if you dont know what Shinigami are then i will tell you what thy are

Shinigami are a race of spiritual beings that act as enforcers and psychopomps who all share similar supernatural powers. They are souls with a high level of innate Spiritual Energy, recruited from the ranks of the residents and nobility of the Soul Society. Like all spirits, they cannot be detected by normal humans. Shinigami use their Zanpakutō, supernatural swords that are the manifestation of their owners' power, to perform soul burials on Pluses. Shinigami also use their Zanpakutō as well as magic known as Kidō to fight their arch-enemies, the Hollows