One of my most fun characters ever was a priest of a raven god, Pathfinder, with Trickery, Memory, and Travel (I think) as domains. We faced a massive fortress filled with giants and trolls, but without sentries capable of seeing an invisible flying intruder. After all, what could an invisible flying intruder do?
Cast confusion into the barracks just before bedtime, that’s what an invisible flying intruder can do. Range of like 400’, with a radius big enough to catch a good half dozen or dozen giants; even the ones that made their saves were pretty quickly drawn into the fight to the death.
I felt kind of bad about that one.