Moroni is the name of the messenger angel, aside from Gabriel. Moroni was specifically the angel, who spoke to Joseph smith in his dreams. Although his origin is unknown, it is said that he was a native moron. But although he was from there, he was white skinned. When asked why, he spoke of the curse. When his people has a tribe in Moro, they were attacked by other rival tribes. But God got angry with them and cursed the attackers with black and red skin.
Moroni is a well appreciated saint in Mormonism and has his own shrine in the north of Promised Land. He is warshipped and prayed to. In times of ignorance, he is called upon as a spiritual guide. This i called Moriniism and is a branch of Mormonism.