Undead bones that yet burn.
Cast it into the shrine bonfire to boost the recovery provided by the Estus Flask.
The bonfire's cinders are bones of Undead, and a bone that still burns is a fresh cinder indeed. Before feeding upon death, one must first pray to it.
- A shard can be found in the Undead Settlement after the Dilapidated Bridge bonfire, near the tree being hounded with arrows.
- In Farron Keep inside a structure near the ladder to the Farron Wolf, surrounded by slugs.
- One can be found in the Cathedral of the Deep. From the Cathedral of the Deep bonfire, head along the path into the graveyard. Take the left path until you reach another clearing, then take the right path until you reach the stone staircase. Proceed upwards to the central balcony area. Next to a gravestone overhanging the side of the cliff is the shard.
- Another can be found in Irithyll of the Boreal Valley. From the Church of Yorshka bonfire, proceed through the passges to reach the wooded area. Head to the right until you reach a tombstone, behind it is the shard.
- In Irithyll Dungeon, from the Profaned Capital bonfire, head downwards until you reach the ladder going back up, climb up and next to the bonfire is the shard.
- From the Dragon Barracks bonfire in Lothric Castle, head up the staircase to the right, and then continue forward to the bridge with the dead white dragon in front of it. Drop down to the left from the bridge and go under to find the shard.
- In the Grand Archives of Lothric Castle, from the elevator head up through the library, taking the staricases going upwards. Continue until you reach the outside balcony, where you should drop down onto a lower balcony, running past the Gargoyles, past the Crystal Lizards, and across the rooftops to enter the inside balcony with the pedastal on it. On the pedastal is the shard.
- From the Abyss Watchers bonfire, enter the Catacombs of Carthus, heading to the left, then to the right across the bridge platform into another room. Go right towards a staircase, proceed down it and out of the room to the right. Go down the large staircase, avoiding the skeleton ball. Kill the skeleton that stands in the corner of the room after the staircase. Once the skeleton ball returns, it will explode and the shard will drop.
- From the Demon Ruins bonfire in Smouldering Lake, head into the cavern and kill the Carthus Sandworm who drops the shard.
- From the Old King's Antechamber in Smouldering Lake, head straight forward, entering the room to the left after turning a corner. Once you enter the rooms with the Smouldering Bastard Ghrus, take the passage to the right. You will eventually reach a large room with two Demon Clerics. Reach the other side of the room and the shard can be found on the left-hand wall. Watch out for the Smouldering Rotten Flesh that drops immediately once you pick up the shard.