In Doctor Strange In The Multiverse Of Madness, Chthon is mentioned, the demon who created the Darkhold and carved the first spells on Mount Wundagore. At this point, the opportunity was missed to mention the clandestine war between the Helstrom brothers and the Blood against Mother and other demons, events seen in the Helstrom series. This would have made it clear that there were recent events involving demons.

In Werewolf By Night, it's mentioned that monsters and supernatural threats have always existed in the world, and that there were hunters tasked with eradicating them. At this point, the opportunity was missed to reveal that the hunters summoned to fight for possession of the Bloodstone were part of The Blood, an organization seen in the Helstrom series composed of demonologists and monster hunters who have been secretly active for centuries.