"Wait, wait, wait... TeleriB doesn't write the In Nomine content. What's up with this?"
7th Sea mentions that angels are part of Vaticine (and one assumes Objectionist) tradition. There's not a whole lot of detail, but there is an idea that Theus has helper spirits which can be tasked to move about the mortal plane.
Who fills the symbolic and artistic void where we find Michael and Gabriel in our world?