With Absolutely No Speculation, What Lore Details Did We Learn in Ashes of Ariandel?

The following was originally posted in this thread by pocketlint60, and all content contained is credited to them. Only minor changes were made to accommodate the difference in format. 

• Sulyvahn was born inside the Painted World.
• "Cold" is related to Sorcery. This was heavily implied before but finally confirmed with the existence of several frost sorceries.
• Sulyvahn was the foremost pioneer of frost sorceries that we know of, and possibly the only one.
• The citizens of the Painted World are outcasts of all kinds.
• Blood has inherent mystical powers, and is capable of "appeasing" flame. This is the first explicit reference to blood related magic in Dark Souls, although the Wolfsblood of Farron comes close.
• The Painted World was painted with blood.
• The Painted World is periodically infested with rot and cleansed with fire, like a smaller scale version of the cycle of Light and Dark. The Sable Church challenges this cycle, just like they challenge the Linking of the Fire.
• The scythe is considered to be symbolic of a home long lost by the people of the Painted World.
• The oldest of the founders of the Sable Church is Elfreide.
• The Pus of Man is definitely Abyssal in nature; the Follower Torch says "Some forms of the Abyss manifest as pus within the body, treated from ancient times with fire."
• Back when the "imprint left by the gods still ran deep", there were things called "aureoloes" that are comparable to Miracles in...some way. An aureoloe is the radiant halo that most sacred or divine people were drawn with in medieval paintings.
• Despite the fact that the Painted World is named after him, Ariandel is only the "restorer" of it.
• The Farron Followers were tasked with killing Farron warriors if they ever became infected by the Abyss.
• There is a fabled forest called Millwood. The savage yet spiritual people of this land worshipped a tree called the Ethereal Oak. For unspecified reasons, the forest was destroyed and the Oak rotted away. No corpses were found, but everyones' things were left behind. This is because the knights of Millwood made their way to the Painted World.
• The Millwood Knights are sworn enemies of "The Abyss Dragon", but their hatred for it faded over time as they lived in the Painted World.
• Undead slaves were forced to serve as soldiers. It's not said who they fought for, only that they were never relieved of duty even when they lost their minds and their bodies became deformed. Despite this awful treatment, the Undead Slave Knight set is of fine quality, which makes it a symbol of honor.
• Freide, Sister of the Painted World, "renounced everything" before discovering a people she wished to protect. Because of this, she "assumed the precise form that they yearned for."
• Sir Villhelm served Elfreide, and was regarded as a cold blooded hang-man. However, he resigned from his duty by accepting the Onyx Blade.
• The Clerics of Smouldering Lake are responsible for unique pyromancies derived from the Chaos of Izalith.
• At some point, Undead warriors fought each other for sport, knowing full well they couldn't die. The champion of the Undead Match eventually went mad, and in the end only his page and his wolf were there to attend to him.

I'm honestly on the fence about whether this isn't enough and just raises more questions, or if they added some interesting new side stories while revealing some important details about the nature of the Dark Souls universe. Be sure to tell me if I missed anything, and share your opinion on whether you think this was enough lore, too much, too little, etc.

Added by Tardivex:

"I also would like to add (as I mentioned on another post) that Friede is one of Yuria's sisters, here's some dialogue I've got from Yuria after beating her, could be after you meet her too I'm not sure."

Transcript:

"Ahh, our Lord and Liege.

Twas the soul of my sister.

Elfriede... A poor wench turned to Ash, who would abandon Londor...

If thou wouldst, let it nourish thy Lordship.

And in return, do her one small kindness.

Remember those who stayed by her to the end, in the shadows cast by fire...

And lastly, my Lord, take up thy rightful mantle, of usurper."