Made this description up for Sariel in case she returns in the windows era:
“Sariel
Angel of Death
Species: Angel
Abilities: Manipulation of death, soul transfer
Age: Old as time itself
Occupation: Mistress of the Fallen Temple and Ruins of Vina
Location: Makai and Heaven
Sariel is one of the two final bosses of Highly Responsive to Prayers. Unlike Konngara, Sariel has a second form, which Reimu struggled to overcome. Despite living in Makai, Sariel is actually not one of Shinki’s creations. Rather, the two are sisters, having moved to Makai shortly after Shinki created the realm. Sariel is also the mother of Elis, the father being a yet unnamed vampire.”
Btw this is pretty, nice use of the Undertale save point