Kuromaro is a fallen god cursed to bring eternal darkness wherever they're summoned. They live completely isolated from other gods and beings—pretty much as cut off as it gets. The interesting thing about Kuromaro is that they're shapeshifters of sorts: they present as male when appearing to Nanami and female when dealing with Ookuninushi.
Meeting Kuromaro takes some effort. Nanami manages to get another deity to call them during her second trip into the past, but she doesn't actually encounter them until her third visit. That's when Kuromaro finally opens up about their history with Tomoe.
Content compiled by AnimeList.moe from publicly available sources.
