DEFINITIONS

Heaven:
God is the ruler of the world. He is able to create lives, protect them and to control the weather.
Angels are servants of God. They are working very hard to fulfill their missons. According to their effort, they will be able to reach a new level. (there are four levels) However, they are invinsible for ordinary humans.
Kuroi No Tenshi are the start level of an angel. They are small and have black wings.
Riyu No Tenshi are the second level of an angel. They are small like the Kuroi No Tenshis, but their wings are white.
Sora No Tenshi are the thrid level of an angel. They will become tall like ordinary humans.
Archangels are the highest level of an angel. They are working directly under God in the heaven.

Demons
Satan is the nemesis of God.
Yokai No Kishi are half humans and half demons. They are invinsible for living humans without any spiritual powers.
Demons are created beings by Satan and they are very selfish.
Raku No Tenshi are angels who have betrayed God and serve Satan.