Alastor mentions he had a "back door" available thanks to Charlie owing him that favor.
The eyes of Adam's mask glitch when he tells Charlie he will kill her. This may have signaled Lucifer that the deal to leave the hellborn demons alone was broken.
The new Hazbin Hotel reflects Charlie, Vaggie, Angel, Husk, Pentious and Alastor in some of the designs. A memorial portrait of Pentious and statue of Dazzle are included to honor them.
It's proven Charlie's idea works. Emily is so happy to see that it does, she squeaks a smile. Sera, however, is shocked her jaw drops.
It unknown if any of the Cannibals survived as they are no in the crowd when Adam is defeated. It's possible they were all killed trying to eat the angel corpses early.