Well, that was...a lot to take in. Salem and Ozpin (actually Ozma) fell in love when the latter rescued the former from her lonely tower in a time when humanity had Magic and the Gods lived among them, then Ozpin got struck down by disease. Salem pleaded the Gods to revive her and managed to manipulate the God of Destruction to do so, angering the God of Light, who revealed Salem's deception, thus angering both to the point of cursing Salem with immortality to learn from her mistakes. All she learned was that humans are patsies and can be easily turned against each other and the Gods. The God of Destruction wiped out humanity and left Salem alone, also shattering the Moon. The God of Light offered Ozma the chance to make things right, telling him cryptically that Salem wasn't who she used to be all while not telling him the whole truth behind the destruction of Humanity, and Ozma and Salem met again, deciding to give love a try again to unite humanity under a single banner and also having 4 daughters who could use magic. Ozpin eventually got cold feet, fessed up to everything, and tried to sneak out with his daughters. Salem, having none of that, engaged in battle with Ozma that killed him and their children. Eventually, after several reincarnations, Ozma asked if he could destroy Salem, and the answer was no.