Must have rabies - look at the crazy eyes!
I awake underneath a tree with only one way to go - a clearing with a not so friendly manticore. After crushing the beast I found myself at a small shrine with a talking shroom named Elizabeth. She tells me Princess Dusk has been kidnapped (that was quick) and like any good Mario I should save the princess! Well, I'm here anyway so why not. The nearby and eerily familiar forest is filled with gardener-type spriggans as well as gigantic knight statues who I opt to stay away from. There's also a black dragon.
After much running I find a quiet area that unlocks some handy elevator shortcuts. A shady guy named Chester is here too, selling some stuff and being a bit of a douche. I'm not the only one who was dragged here he says. I slightly suspect Chester's related to Ser Dick. Anyway, at a nearby Colosseum I witness a strange, beholder head hollow getting thrashed by a mighty knight. Who then sets his sights on me! Turns out this is Artorias the Abysswalker, after the abyss had corrupted him.
I just wanted to return your ring, you psycho.
He is a tough fight because learning all his moves (amazing to watch, less so if it connects) takes some time and more than a few attempts. Ultimately I end up face tanking him with the pyromancy called Iron Flesh. This stunts his DPS enough for me to outlast him and ultimately put him in the ground. After the battle a lady knight named Ciaran appears and gives him a proper burial, asking if I could give her the soul of Artorias. Since I sense a connection there I hand it over and she gives me her twin daggers in exchange - stating she wouldn't need them any more.
Turns out this was the Lord's Blade Ciaran, one of the four best knights of the King (Gwyn, I assume). I had already met (and slain) two of the others: Artorias and Ornstein.