Dark Souls Lore
My knowledge of the lore is great, so allow me to share it.
The Beginning
In the Beginning, there was nothing. No light, no dark, no death, only grey. Immortal dragons ruled the over-world as mindless husks wandered in the darkness of the underworld. But then, there was fire. Fire was spit into the underworld, giving the husks minds, feelings, and most importantly; souls. Four exceptional souls were discovered: Gwyn discovered a soul of light, and power, allowing him to harness the power of lightning and miracles. The Witch of Izalith discovered a soul of life, and fire, allowing her to harness the power of pyromancy. Gravelord Nito discovered a soul of death, allowing him to harness the power of curses, poison, and plague. The fourth soul that was discovered was called the "Dark Soul", which was split into many pieces and passed down from person to person, creating humanity, and the undead.
Gwyn's Age of Fire (Pt. 1)
With the soul of light and power, Gwyn built an army of Silver Knights, to attempt to exterminate the dragons in the over-world. The first attempt was unsuccessful, as the dragons' invincibility originated from their scales. Seath, a scaleless dragon, was jealous of his brothers' immortality, therefore he betrayed them by telling Gwyn how to peel scales off of the dragons in an instant. With lightning. Gwyn taught his faithful army the art of miracles, and with their lightning and superior healing abilities, they were able to crush the dragons above, placing them on the verge of extinction. Gwyn built an empire over their corpses, the capital being Anor Londo. Seath was given the title of Duke for his betrayal of the dragons, and given a seemingly endless source of knowledge where he could study how to become immortal without the use of scales. Many other landmarks and cities were created as well. Gwyn also created New Londo, a city for the four kings who were highly trusted by Gwyn, as each of them held a fragment of the dark soul. Sen's Fortress was erected as a prison, with towering giants and humans spliced with some dark magic to create Snake-People to guard the prison. The Kiln was constructed to house the first flame, and that is where Gwyn spent much of his time. The Witch of Izalith created Izalith (of course) which housed The Witch and her children. Blighttown was created by the dwellers of the Great Swamp, many of them being pyromancers. Nito built the Catacombs, and the Undead Church to give the undead a place to call home. This empire lasted for a few hundred years, but the flame began to dwindle.
The Birth of Chaos
A prophecy was foretold of Gwyn's reign coming to an end, and the Age of Dark beginning. Gwyn denied this, and when the flame dwindled, he ordered the Witch of Izalith to create a new flame, to replace the last. The Witch did as she was told, but not without severe consequences. The flame spiraled out of control, Either killing or severely deforming the Witch and her children. The Witch became the Bed of all Chaos, creating demons who would sometime become nomadic, and destroy anything in their path. Quelaag and her sister Quelaan, were malformed into half-spider creatures, and accidentally flooded Blighttown and the Great Swamp with poison, toxins, and fire. The inhabitants of Blighttown were transformed into toxic abominations, and those that weren't bore the eggs of Quelaan, and were poisoned by the extremely painful and life threatening poison known as Blightpus. Unable to bear the guilt of poisoning the poor souls of Blighttown, Quelaan sucked the Blightpus out of all of the egg-carriers, making them devote their miserable lives to her. Quelaag (Quelaan's sister) became enraged, and killed those who wanted to enter Izalth or her sister's home. Quelaag gave the humanity of the trespassers to her sister, as it eased the symptoms of Blightpus. The single brother became a giant hulking abomination, forever grieving the death of his most favored sister. This lowered Gwyn's hope even further.
The Four Knights of Gwyn
Four knights were given the highest honor and the gift of being a Demi-lord. Dragonslayer Ornstein (one of my favorites) was inducted into the knights because of his unbreakable will and the countless amount of dragons he slew. Hawkeye Gough was given the title of one of the Four Knights because of his pinpoint accuracy. It is said that he could hit a dragon right in the middle of it's eye from a kilometer away. Lord's Blade Ciaran was given her rank in the Knights because of her superior skills of stealth and assassination. She was also the only knight in Gwyn's army that was a woman. And finally, (My favorite character) Artorias the Abysswalker. He was given a White Direwolf pup at birth which he decided to name Sif. They grew to love each other, and stayed together when he was inducted into the Four Knights. Artorias got into the Knights because of his divinely blessed sword, shield, and his skills with miracles. After serving some years in the Knights, Ciaran became romantically interested in Artorias. I'll expand on this later, but now for Manus.
^ Artorias and Sif
Manus, Father of The Abyss
In a faraway land named Oolacile, there were amazing scholars and mages. But these great minds feared the prophecy of the Lord of Darkness. Their solution was to imprison and torture the first holder of the Dark Soul: Manus. Manus originally was an undead with a normal family, until the mages of Oolacile took him away to be eternally tortured in their dungeon. But when Manus was taken away, he brought one last remnant of his old life so that he would not go completely insane from torture. Manus' room had a bonfire inside of it, so if the torturers accidentally killed Manus through their torture, he would simply regenerate there for more torture. The one thing that kept Manus from going hollow was his pendant that he had kept secret from the torturers, until they found it, and crushed it in front of his eyes. When the torturers left Manus' room, he broke out of his shackles. His anger compelled him to repeatedly slam the side of his cell with his fists. He did this hours upon hours, until it finally broke. What he found behind that wall would change him forever. It was The Abyss. Calling to him. Luring him to it's dark embrace. It promised him power, revenge, and dark, in exchange for it's spread. Manus accepted, and became a hulking monstrosity of pure dark. He either killed or corrupted all of those who tortured him, and searched the land for his broken pendant. He became outraged when he could not find it, so he used the Abyss to pull those who were unfortunate enough to find his broken pendant in the future to the past.
The Crisis of Oolacile
Gwyn saw Manus as a threat to his power, so he sent Artorias to deal with him. It pained Ciaran to see him sent to a horrid place such as Oolacile, but she was patient. She decided she would wait for a few months, just in case any other problems arose in Anor Londo. Artorias and his companion carved through the dark, but every corrupted citizen of Oolacile's blood made Artorias' sword weathered with dark, so when he made it to The Abyss itself, it was almost completely dark. A small ways into The Abyss, Sif became cornered by the creatures in The Abyss. Artorias used the divine power in his greatshield to protect Sif from the corruption. But alas, the creatures were too powerful for him to fight, so he left Sif with his shield and carried on to Manus. When Artorias finally confronted Manus, his sword was too corrupted with dark to be effective against Manus. But Manus did not kill Artorias, all he did was swipe him once with his staff, which corrupted Artorias' soul, malforming him into a creature on The Abyss, but still remaining in his humanoid form. When Gwyn heard nothing from Artorias, he sent Gough and Ciaran to Oolacile to find him. Much to their disappointment, theyfound a corrupt Artorias fighting a brave undead warrior. After Artorias was defeated by the undead, Ciaran erected a grave for Artorias, and grieved over that grave for the rest of her life. Gough witnessed the destruction of Oolacile, and lost all hope. He retired to making wood carvings out of Archtrees.
Gwyn's Age of Fire (Pt. 2)
Demons attacking Anor Londo. Silver Knights going to Izalith with shiny new Silver armor, coming back with armor scorched as black as The Abyss from the flames. The First Flame, dwindling. Gwyn's daughter, and many other citizens of Anor Londo were evacuated. Gwyndolin, Gwyn's son, created the illusion of the princess, the Silver Knights, and the sun to try and make people still think that Anor Londo is still powerful. But the truth was, the Age of Dark was rising, and it was spreading quickly. It had overtaken the city of New Londo, with Darkwraiths roaming the blood-soaked streets searching for more lives to claim. Gwyn had no choice but to flood the entire city, killing millions. Gwyn's last act was sacrificing his soul to the First Flame, leaving a mindless husk of his former self roaming the Flame's kiln. And that, is where the game starts. You are the Chosen Undead. It is foretold in the Prophecy of Old that the Chosen Undead would travel to the kiln either become the new Lord of Sunlight, or become the Lord of Darkness. What will you choose?