Lucavi

The Lucavi are a group of demons from Final Fantasy Tactics, who are working in secret under the cover of the Murond Glabados Church to revive their dead leader Altima, who is also none other than Saint Ajora. There are at least seven Lucavi, though one of them, Eilidibs, is not necessarily connected to the other six. Each Lucavi is connected to a Zodiac Stone (called "Holy Stones" by the Glabados Church), which serves as a conduit for that Lucavi to exist in Ivalice. Each Lucavi also has a human host, allowing them to interact with others in Ivalice without drawing attention. The Lucavi are capable of switching between human and demon form via their Zodiac Stone.

The Identities of the Lucavi
Queklain, the Impure King, is associated with the Scorpio Holy Stone, and has possessed Cardinal Draclau. Velius, the Warlock, is associated with the Aries Holy Stone, and has possessed Wiegraf Folles. Zalera, the Angel of Death, is associated with the Gemini Holy Stone, and has possessed Marquis Elmdor. Adramelk, the Ghost of Fury, is associated with the Capricorn Holy Stone, and has possessed Dycedarg Beoulve. Hashmalum, the Regulator, is associated with the Leo Holy Stone and has possessed Vormav Tingel. Altima, the Bloody Angel, is associated with the Virgo Holy Stone, and has possessed none other than Saint Ajora himself.

The Attempt to Revive Altima
Altima is the leader of the Lucavi, but in her absence Hashmalum is left to lead the effort to revive her. Ramza runs afoul of the Lucavi by discovering what they're up to, and Ramza is forced to fight and defeat the Lucavi one by one. By the time he catches up to Hashmalum, however, he is dangerously close to reviving Altima. Ultimately, Hashmalum succeeds by committing suicide himself (Altima's resurrection requires lots of bloodshed). Ramza then battles Altima, who transforms into a giant skeletal monstrosity mid-battle. This is still not enough, however, and Altima is destroyed, though the resulting explosion devastates the area, and it appears that Ramza has perished as well. However, Ramza is seen by Olan Durai, so it appears that Ramza managed to survive the Bloody Angel's demise.