Aru Ilúvatar, Father of All

Aru Ilúvatar, The First

Aru Ilúvatar is known as the creator of all existence. In Elvish, Aru means "The One", or "He that is Alone" and Ilúvatar signifies "Father of All". These names appear in the Libram of Legendarium, both in isolation and paired (Aru Ilúvatar).
Aru is a supreme being, analogous to God. Aru is transcendent, and completely outside of and beyond the world. He first created a group of angelic beings, called Valari, (Angelic powers), these holy spirits were co-actors in the creation of the universe through divine music and chanting. Aru alone can create independent life or reality by using the imperishable flame. All beings not created directly by Aru, (e.g. Dwarves, Ents, Griffins), still need to be accepted by Aru to become more than mere puppets of their creator, by giving them sapiense through the flame.

Exerpt of the libram of legendarium
Aru infuses a part of himself when he creates life. Some of his spirit lives within all lifeforms. This light that lives within us is more known to mortals as the soul. The soul is pure and consists of Aru`s true light. As more lifeforms are born, Aru fades, as a part of his spirit is distributed among each body.

When mortals die their souls travel into the void and embrace their lord as something more than just his former newborn spirits. They return as individual souls that have lived out their lives on Middle-earth and experienced its joys and sorrows. These souls restore Aru and strenghens him even more than before.

After the betrayal of his firstborn Melnikor, the corrupted souls are unable to venture back to Aru`s embrace, but is instead drawn to the evil that surrounds his son. The more souls that Melnikor (Morgoroth) attain, his powers grow, and when he is strong enough he will be able to cross over into the mortal dimension and destroy Middle-earth, and the universe with it. In the wake of his destruction he will convert any mortal souls with his dark hatred and grow to the peak of his powers, and finally be able slay Aru, his father.

This will mean the end of all creation. The dark one will then become the new Aru, he that is alone, with the imperishable flame in his posession.