So Nebuchadnezzar, he put the children in a fiery furnace
Poured on the coals, red hot brimstone!
and made it hotter, seven times hotter, hotter than it oughta be,
But the Lord sent a snowy white angel
Down into the middle of the fire...
-Shadrach, Meshach, Abednego
Gabriel, the Ofanite Archangel of Fire, is a controversial figure in Heaven, ever since she was accused by Dominic of warping the text of the Qu'ran towards her own ends. Already on edge due to sharing a Word with Belial, she snapped under the pressure of the accusation and stormed out of Heaven. Dominic would still like to get his hands on her to get some answers, but it would be quite the feat to haul the primordial Archangel back.
Gabriel represents not only the physical concept of Fire, but also its symbolic associations with passion and obsession. She's said to speak directly with God, as Yves allegedly does. From an epistemological point of view, it's difficult to confirm or deny this, but she does sometimes seem to mumble strikingly accurate (if illucid) prophecies that suggest it's true.
Gabriel's Servitors are a fanatic bunch, and not known for subtlety. They hunt down and punish the cruel. It is dissonant for a Servitor of Fire to let a truly cruel person go by without feeling God's wrath. What form that wrath takes varies from case to case. Servitors of Fire claim they just know what the universe demands.
Gabriel's not known to be involved in Advincula. But, then, the cruel are everywhere.