The Last Purge
Lucifer's many years ruling Hell took a toll on how he trusted others. He questioned the loyalties and intentions of all those around him. All except the two who fell with him. Those, he could never betray. Beelzebub and Leviathan were the only things Lucifer loved.
When Lucifer received Beelzebub's head and seven hearts as a gift at the foot of his throne, he didn't know what to think. He wondered if it were a trick, then declared that he would eternally skin whoever dared to try to trick him. And finally, he realized that Beelzebub was truly dead.
It was obvious this was a move against him. Since he couldn't decide who, Lucifer slaughtered the Princes Asmodeus, Berith, Astaroth, Verrine, Gressil, and Soneillon, the only ones in Hell he thought would be strong enough to lay a hand on Beelzebub. Hell trembled under his rage.
Just a day later, another gift appeared at Lucifer's throne: Leviathan's eyes, and one of his hearts. There was no ransom. There were no notes. There was only... pain, and the profound sense of grief.
The next day, he left.
Within three days, Hell had been torn asunder and the chaos was all-encompassing. Lucifer's absence upset the balance between Heaven and Hell and manifested itself as earthly disasters. The Princes of Hell couldn't decide who should rule as King while Lucifer was taking a... hiatus. War ensued. War in Hell meant plague, death, and destruction on Earth. That translated into parts of Heaven running on the dysfunctional side.
With Hell in shambles, the Infernal Gates sealing it from Heaven and Earth have weakened. Ordinarily, one would have to be very well-versed in magic or on a one-way trip into Hell to gain entry. But now, all it takes is ambition and dedication.
I sold my soul to the devil. And we're going to get it back.
Two Weeks Post-Purge
The Resurrection spell worked.
YOU are a sorry excuse for a human. You sold your soul to the devil in exchange for whatever petty things humans lust after these days. In exchange for your physical body, you allowed a Prince of Hell to possess you in order to fulfill two goals: put Hell back into this demon's hands and get your goddamn soul back.