EVerything we know and love of Middle Earth and the lore of Arda.....
I'll start off.....
Eru,The One is the god of the people's of arda.
He created 15 Valar...
1.Manwe
2.Varda
3.Ulmo
4.Alue
5.Yavanna
6.Orome
7.Mandos
8.Nienna
9.Irmo
10.Vana
11.Nessa
12.Vaire
13.Este
14.Tulkas
15.Mekor
and other lesser spirits called Maiar.

Melkor was the most powerful of them and he during the initial themes of creation rebelled against The One and made Arda a place of conflict.