Cursed moonflower
A dark figure, with no face or figure just like a shadow, spread the room in pure darkness. A venomous spirit. They are fallen angels who once decided to become human. Once they died, they couldn't enter heaven or hell. In vengeance, they wandered the earth for aeons and every time a celestial being is born, they would be most eager to take over their body and kill the body to return to the heavenly realm.
Even though Sarael's spirit was still not awakened, her secret was too strong, luring them and cursed moonflower makes it easier to return for them. She was like a magnet to them right now.
Sebastian saw it coming, the instinct of survival was still huge. When it comes to survival, evil replenishes. A spirit full of vengeance was sure not something that can easily take over demons but that spirit was not alone. It just fought off his all enemy before getting the winning steak as Sarael. Someone who defeated so many spirits was already powerful.