Avalon Morningstar is Charlie's older sister and best friend. Charlie doesn't see a lot of her sister because she always at Overlord meetings. But she does come back home after Charlie opened the Happy ( Hazbin) Hotel, to help her out and not mess up her interview at the 666 news. Which she does, causing the Radio Demon aka Alastor to turn up at the Hotels doors. Avalon and Alastor know each other because of all the meetings they attended. But they never really talked to each other. That doesn't stop them falling for each other.