After a long grueling process, you have finally defeated Artorias the Abysswalker and collected his soul. You left the Arena shortly afterwards to continue your journey. After a while you decide to head back to the Arena, where, you saw a feminine figure in blue armor, wearing a white mask, kneeling in front of a tombstone that appears to be located in the spot where you once killed Artorias. She notices you

"...You, is that not... The soul of the man who fell on this spot, he was a dear friend. I wish to pay proper respect, with that Soul. Would you be willing to part with it?" She asks as she continues to kneel and bow her head in front of the gravestone.