The name of the Angel isn't given but we are told that he was given much incense and that he offered it with the prayers of the Saints.
These Saints were the Saints of the Tribulation Period and their prayers were for deliverance from their enemies.
This accounts for the Angel filling the Censer with fire from off the altar and casting it on to the earth, with the effect seen in the voices and thunderings, that broke the silence of Heaven and the lightnings and earthquake on the earth.
The same things happened when the Seventh Trumpet sounds and the Seventh Vial is poured out.