Romeo and Juliet are the most well-known people from feuding families to fall in love, but what about creatures who come from opposite feuding worlds?
Saga, by Brian K. Vaughan and Fiona Staples, has two entities from worlds that have been at war with each other forever. Nobody even knew that Wreathers and Landfallians could have children with each other, but these two manage it.
Demons falling in love with angels, werewolves with vampires, witches with vampires, and so on. Which pairing is the most opposite?