You can now advance to the end of the game by placing each of the "Cinders of a Lord" on the thrones in Firelink Shrine and then examine the bonfire to travel to the Kiln of the Flame.
Depending on the course you’ve taken up to this point you can obtain 1 of 4 endings:
Ending 1: You must have no Dark Sigils or heal the Dark Sigil at the Firekeeper
After the boss lit the bonfire to receive the ending "To Link the First Flame"
Ending 2: You must have given the Fire Keeper Soul and Eyes of a Fire Keeper
After the boss summon the Firekeeper to receive the the ending "The End of Fire"
Ending 3: You must have given the Fire Keeper Soul and Eyes of a Fire Keeper
After the boss summon the Firekeeper, but strike her before she finishes the ritual
Ending 4: You must have gained all 8 Dark Sigils
After the boss lit the bonfire to receive the ending "The Usurpation of Fire"
WARNING : Killing the Firekeeper (Ending 3) will prevent you from obtaining any trophy/achievement for that ending. If you wish to gain a trophy/achievement, do not kill her until you have successfully completed all other endings.
Note: You can summon Yuria or Londor and Londor Pale Shade to each of the endings, except the ending that requires you to heal the Dark Sigil.