Lore
Kos is a Great One whose carcass was found washed up on the coast of an apparently isolated fishing hamlet. If the player looks closely, they can see that Kos has a very humanoid face, with long tendrils where hair should be. This might explain why Kos' Orphan is so humanoid in appearance to begin with.
Theories
Brain Fluid is Kos' blood
When Kos washed up on the coast, its insides were teeming with tiny parasites, unlike any found in humans. In the early days of the Healing Church, the Great Ones were linked to the ocean and so the cerebral patients would imbibe water and listen for the howl of the sea. Brain fluid writhed inside the head, the initial makings of internal eyes. It may be that this 'water' was actually blood, or at least contained the parasites found in Kos.
Kos was murdered by the Brygenwerth Scholars
Rakuyo description:
But one day, she abandoned her beloved Rakuyo, casting it
into a dark well when she could stomach its presence no longer.
Accursed Brew
Skull of a local from the violated fishing village.
The inside of the skull was forcibly searched for eyes,
as evidenced by innumerable scratches and indentations.
No wonder the skull became stewed in curses.
They who offer baneful chants.
Weep with them, as one in trance
Befuddled Villager dialogue:
“Byrgenwerth, Byrgenwerth… Blasphemous murderers, blood crazed fiends. Atonement for the wretches…
by the wrath of mother Kos. Mercy for the poor wizened child, mercy. Oh please, atonement for the wretches.
Lay the curse of blood upon them, and their children, and their children's children for evermore.
Each wretched birth will plunge each child into a lifetime of misery…
Mercy… For the poor wizened child… Let the pungence of Kos, cling like a mother's devotion.”
Simon, the Harrowed dialogue:
"Do you know why the Hunters are drawn to this Nightmare?
Because it sprouted from their very misdeeds.
Things that some would rather keep secret.
A pitiful tale of petty arrogance, really."
Lecture Building Lore Note:
Location: After picking up Note 1, progress to the next room. The note is behind a cage on a table:
"Hunt the Great Ones, Hunt the Great Ones."
Kos was murdered by the people of the Fishing Hamlet
Kos resembles a large white whale, and the creatures of the Fishing Hamlet wield harpoons and anchors. It makes logical sense that they may have killed Kos while at sea, perhaps believing the Great One to simply be another creature of the sea. This may be the reason Kos' carcass "washed up on the coast".
Kos' carcass was also teeming with "parasites". Throughout the village we see thousands of phantasms. Did these phantasms come from the belly of Kos? It seems possible. Their presence may be what caused the occupants of the fishing hamlet to morph and change into the creatures we encounter.
Relationship to Hippocrates, the Greek Physician
Hippocrates, commonly known as the father of modern medicine, was born on the island of Kos. He was most renowned for his pioneering work in the healing and curative arts, a concept that pervades the world of Bloodborne in its use of blood. The connection is ultimately probably just in name and tenuous otherwise.
Some interesting comments from the community explore this further though:
- Could it be that Kos was connected to the Healing Church long before washing up dead on the beach? If I'm understanding what I've read correctly, we still don't know for sure exactly where the first good blood came from, so is it possible that Kos provided the healing Great One blood the Church used to begin its ministrations?
- Miyazaki himself has stated that he puts a lot of thought into names, and wants them to have profound meaning at times. If Kos and the Orphan, and the experimentation done on them after the Hamlet incident helped pioneer the medical advances that Yharnam was famed for (done though the Research Hall, which is replete with medical tools and imagery), then this link may have some credence.
- Hippocrates was mentioned by fake Iosefka. "I swear by my Hippocratic oath…" It is an oath all doctors take in the real world to do right by the patient. Furthermore, Iosefka is all about turning people into sea people. I think there are a lot of references in the game to Greek history and tragedies.
- Hippocrates is very important to Bloodborne. He was also known to mention the act of bloodletting, but he personally did not rely on it in his practices, though he is known as believing that menstruation was a means of women purging their "bad humors". A physician named Galen, who studied the teaching of Hippocrates was better known for advocating bloodletting in a medical capacity.
Sources
Kos Parasite
When the carcass of Kos washed up on the coast,
its insides were teeming with tiny parasites, unlike any found in humans.
This atypical weapon can only be clasped tight and swung,
but a Kos Parasite is said to stimulate phantasms inhabiting a lumenwood
Milkweed Rune
A Caryll rune envisioned by Adeline, patient of the Research Hall.
A translation of the inhumane, sticky whispers that reveal the nature of a celestial attendant.
Those who swear this oath become a Lumenwood that peers towards the sky,
feeding phantasms in its luscious bed.
Phantasms guide us and lead us to further discoveries.
Accursed Brew
Skull of a local from the violated fishing village.
The inside of the skull was forcibly searched for eyes,
as evidenced by innumerable scratches and indentations.
No wonder the skull became stewed in curses.
They who offer baneful chants.
Weep with them, as one in trance
Rakuyo
Hunter weapon wielded by Lady Maria of the Astral
Clocktower.
A trick sword originated in the same country as the
Cainhurst Chikage, only this sword feeds not off blood, but
instead demands great dexterity.
Lady Maria was fond of this aspect of the Rakuyo, as she
frowned upon blood blades, despite being a distant relative
of the queen.
But one day, she abandoned her beloved Rakuyo, casting it
into a dark well when she could stomach its presence no
longer.
Brain Fluid
Greyish amoeba-shaped brain fluid. Wobbles and bounces.
Extracted from a patient whose head expanded until that
was all that they were.
In the early days of the Healing Church, the Great Ones
were linked to the ocean, and so the cerebral patients would
imbibe water, and listen for the howl of the sea.
Brain fluid writhed inside the head, the initial makings of
internal eyes.
Plain Doll dialogue:
After defeating Orphan of Kos (The Old Hunters DLC) but before attacking the black shadow:
"Oh, good hunter. I can hear Gehrman sleeping. On any other night, he'd be restless. But on this night, he sounds so very calm. …perhaps something has eased his suffering"
Micolash, Host of the Nightmare dialogue:
"Ahh, Kos, or some say Kosm… Do you hear our prayers? As you once did for the vacuous Rom, grant us eyes, grant us eyes. Plant eyes on our brains, to cleanse our beastly idiocy."
Befuddled Villager dialogue:
“Byrgenwerth, Byrgenwerth… Blasphemous murderers, blood crazed fiends. Atonement for the wretches… by the wrath of mother Kos. Mercy for the poor wizened child, mercy. Oh please, atonement for the wretches.
Lay the curse of blood upon them, and their children, and their children's children for evermore. Each wretched birth will plunge each child into a lifetime of misery…
Mercy… For the poor wizened child… Let the pungence of Kos, cling like a mother's devotion.”
While using a Milkweed Rune:
“Curse here, curse there, a curse for he, and she. Why care? A bottomless curse, a bottomless sea, source of all greatness, all things that be. Listen for the baneful chants. Weep with them as one entranced. And weep with us, oh weep with us… [sobs]
Listen for the baneful chants. A call to the bloodless wherever they be, a call to the bloodless wherever they be. Fix your ears to hear our calls. “
Final cutscene:
“Ahh… Sweet child of Kos, returned to the ocean.
A bottomless curse, a bottomless sea, accepting of all that there is, and can be.”
Fishing Hamlet Chanters dialogue:
"Mother is dead"
"Her baby…"
"A bottomless curse, a bottomless sea, source of all greatness, all things that be. I call to the bloodless wherever they be"
"Do you hear the sea?"
"Kos"
"Dear Kos"
"Curse the fiends, their children too"
"Pray to the blood, forever"
"The lair of beasts"
"Blood-mad"
"Mother is dead, her baby taken"
Simon, the Harrowed dialogue:
"Do you know why the Hunters are drawn to this Nightmare?
Because it sprouted from their very misdeeds.
Things that some would rather keep secret.
A pitiful tale of petty arrogance, really.
High time someone exposed the whole charade."
"Now, now, go on ahead.
You seek nightmares, and the secrets within, do you not?"
At the Lighthouse Hut lamp:
…Oh, you, I’m afraid, I’ve made a botch of things…
…I can hear the bell, now…
…The beast-hide assassin, he’s after me…
…Again and again…
…It never ends…
…Please, I need you to do something…
…This village is the true secret.
Testament to the old sins…
…It feeds this Hunter’s Nightmare…
…Please, bring to an end to the horror…
…So our forefathers sinned?
…We hunters cannot bear their weight forever…
…It isn’t fair, it just isn’t fair…
Research Hall Victims dialogue:
“Splish splash, splish splash, have you heard how curiously the sea churns…?
like a storm but like the rain, only gentle, like dripping water…
it bellows from deep inside of me… here it comes up through my insides,
but gently, like little droplets… “
Saint Adeline dialogue:
First encounter:
Is that you, Lady Maria? No, you're someone else.
Please, could you do something for me?
I need Brain Fluid. Murky, mushy Brain Fluid…
Give Brain Fluid:
Oh, thank you, you're terribly kind.
Ohh… it's wonderful.
And, oh! I hear the sticky sound. Do you hear it, too?
Oh, I know. Will you have my blood, as thanks?
I'll have you know. I was once a Blood Saint, too.
Accept Blood:
That makes me happy.
But I cannot move. Look, on my right arm.
I'm sorry to trouble you, but you don't mind, do you?
Talk again
Oh, there you are.
Don't be greedy. As they say,
Fear the thirst for blood.
I should know. I was once a Blood Saint, too.
Second "encounter”:
Hello, hello, is anyone there?
Please, somebody, I need help.
I'm trying, but I'm afraid the sound is fading…
Hello? Is that who I think it is?
Please, oh please, I need Brain Fluid.
The sticky sound is fading fast.
Please, bring me Brain Fluid.
I must have it… that sound, it is all that guides me…
Without it, I'll be sent back…
To my former, lesser years…
Give second Brain Fluid:
Yes, that's it, let me have it!
Ahh… ahh! I can hear it, yes! That sound that guides me.
Ahh… ahh…
Thank you, thank you so much. You have saved me.
Take this charm. Lady Maria gave it to me, but it is all I can offer,
other than my own blood.
Please, do not abandon me… I promise to do good…
Enlarged Head:
Oh, hello…
One last time, will you fetch Brain Fluid, just one last time?
The murky, mushy fluid that will make me whole.
The sticky sound whispers to me.
So very close, right into my ear.
My head, just a head, that's all there is.
I need my baptism.
Please, I beg of you…
I want to be something…
Enlarged Head [After attacking and getting Brain Fluid]:
Please, give me Brain Fluid.
The sticky sound whispers, I need my baptism.
Ahh, or perhaps, I'm already brimming over…
Give third Brain Fluid:
Ahh, ahh!
Ahhh! Aahh! I see a shape.
My guide, I see your voice, clearly, as it bends and bleeds.
My own, revelation… just for me…
Thank you. For everything…
Really, I used to be nothing…
Lecture Building Lore Note:
Location: After picking up Note 1, progress to the next room. The note is behind a cage on a table:
"Hunt the Great Ones, Hunt the Great Ones."
Byrgenwerth Lore Notes:
Location: On a couch on the opposite side of the same floor as the first note:
"The spider hides all manner of rituals, certain to reveal nothing, for true enlightenment need not be shared."
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Nice article, but could you mention me a source that names Hippocrates as a proponent of bloodletting?
I don't think Hippocrates ever advocated that, and I can find no source claiming he ever did.
I rather believe Galen should be credited with the idea.
Thank you for bringing it up. The theory shall be updated accordingly.
You can view the following the journal on Vojnosanitetski pregled, 2016 73(12):1181-1186 which highlights the contribution of Hippocrates to the field of medicine.