I started out battling a few angels on the back of fighter jet. Yeah. Then once I killed all those bastards with a whipping hair attack followed up with a few shots from my heel guns, a huge demon appeared. I ended up battling that thing as it wove around the top of a train, fending off attacks while whaling on it when it was vulnerable and close. I used umbra magic to summon another demon through a portal on a building to eat the monster - like you do - but then that thing got out of control. I ended sprouting wings and flying around the top of the skyscraper as the demon crawled around it like some freaky drug trip King Kong sequence.