Ebrietas, Daughter of the Cosmos: the Choir's Left-Behind Great One

Ebrietas, Daughter of the Cosmos, is a Great One left behind on Earth and the being the Choir built itself around. The Great Isz Chalice says it "allowed the Choir to have audience with Ebrietas", and the Choir Garb says the Choir took to the skies "together with the left behind Great One". She is an optional boss, hidden in a chamber called the Altar of Despair. (Bloodborne)

What the game says about Ebrietas#

The fullest account is the Augur of Ebrietas, a Choir tool. It is a "remnant of the eldritch Truth encountered at Byrgenwerth" and uses phantasms "to partially summon abandoned Ebrietas." The same text says that first meeting, in the old Labyrinth, "marked the start of an inquiry into the cosmos" and "led to the establishment of the Choir." (Bloodborne)

The Great Isz Chalice adds that it was "the first Great Chalice brought back to the surface since the time of Byrgenwerth", that the Choir was founded on it, and that it let them have audience with her. The Isz Root Chalice records the Choir's belief that Isz "lies in contact with the cosmos". (Bloodborne)

The Choir's research#

What the Choir learned from her pointed upwards. The Cosmic Eye Watcher Badge says the Choir "stumbled upon an epiphany, very suddenly and quite by accident" and asks: "might the cosmos be very near us, only just above our heads?" A note on the way up to Upper Cathedral Ward reads "The sky and the cosmos are one." (Bloodborne)

The Choir Garb says the Choir are both the Church's highest clerics and "scholars who continue the work that began at Byrgenwerth", looking for "astral signs" with the left-behind Great One. Its rites didn't always work. A Call Beyond was meant to reach "the outer reaches of the cosmos" and failed, making "a small exploding star" instead. (Bloodborne)

Where you fight her#

Ebrietas waits at the Altar of Despair, a hidden chamber below the Upper Cathedral Ward, reached through the Lumenflower Gardens. She is found bent over a dead creature on the altar and stays still until attacked. Her spells look like the Choir's own: tentacle bursts that match the Augur, and cosmic blasts. (Bloodborne)

Her trophy calls her a Great One, and her death gives the Great Isz Chalice, which opens the Isz Gravestone in the Chalice Dungeons, where a stronger Ebrietas waits at the bottom. The Altar of Despair matters for another quest too: Queen Annalise's remains can be restored there. (Bloodborne)

What the game never confirms#

The most common theory is that Ebrietas is where the Healing Church's blood came from. It fits: she was found in the Labyrinth, she is tied to the Church's elite, and blood ministration grew from Byrgenwerth's finds. The game never says it, though, and the Old Blood is never traced to her by name. (Bloodborne)

The corpse on the altar is another open question. Its shape looks like Rom, the Vacuous Spider, so many players think Ebrietas is mourning a fellow Kin or a Choir experiment. No text names it. (Bloodborne)

Some players also argue Ebrietas is Kin rather than a "true" Great One, given how much of the Choir's work involved making Kin. The trophy still calls her a Great One, and the game never explains the title Daughter of the Cosmos. For how she fits with the others, see the Great Ones. (Bloodborne)