The Galanthi first appeared in the show's debut episode. In 1896, this tentacled flying being flew over London, emitting bright blue spores that touched many people, specifically the women of London, leaving them with supernatural abilities. After the alien being flew over the city, it vanished and no one who witnessed it remembered it — except for Maladie, who claims the Galanthi was "God," who blessed her.

Three years later, a brightly colored orb is located during an excavation of an underground tunnel. The orb is presumed to be a chrysalis of sorts for the Galanthi. Many are scared of this orb and want it to be destroyed. But instead, the team decides to dig it out to transport it to another location.

Little else is currently known about these alien beings, but they are the source of the supernatural powers many of the women in the time period are experiencing and thus, the catalyst for the show.

At the very least, it's clear to everyone that the Galanthi are not from this time period. But how one managed to appear in 1890s London is still unclear to many. This alien being also seems to have an interesting connection to one of the women.