Yoel is discovered in the earliest part of the Undead Settlement. From the Foot of the High Wall, you descend to a road with Starved Hounds and weaker undead. Kill these targets and look along a desolate stretch to your left. Many petrified pilgrims are there. Look around until you find one that is alive. He’ll talk to you. Agree to let him enter your service and he’ll travel to the Firelink Shrine. There, he’ll help you learn magic. Speak to Yoel in the shrine and he can use Draw Out True Power. This lets you gain a ‘free’ level, but beware, nothing is without cost. Each time he draws out your power you acquire a Dark Sigil item. While in possession of these sigils, each time you die, you gain Hollowing Points, and your appearance becomes ever more corpse-like.

The only way to cure the Dark Sigil is to give the Fire Keeper the Firekeeper’s Soul and pay her in Souls to remove the Sigils. The cost can become extremely expensive, you must pay the cost of your next Level times the number of Dark Sigils you are carrying. Hollowing points (and the curse of your undead appearance) can be reversed by using a Purging Stone, but doing so does not remove the Dark Sigils, only the Fire Keeper can cleanse them.

To fully draw out your strength, you must gain a certain amount of Hollowing. The fastest way to do this is simply jump to your death repeatedly at the shrine and return to speak to Yoel at 2, 6, and 12 Hollowing to gain more Dark Sigils (and levels). Once your Hollowing is progressed enough, he grants you the fifth Dark Sigil. Three more Dark Sigils can be acquired by completing Anri’s wedding questline, and finishing the game with all eight in your possession triggers the Hollow Lord ending.

However, your time with Yoel is limited. Whether you take him home or leave him here, he will not survive deep into the playthrough. If you reach the Catacombs of Carthus, or use Draw Out True Strength five times, Yoel expires. Even leaving him out in the wild will change little, save the location of his corpse. Some things can’t be changed.