Dark Souls III: Deacons of the Deep

Approach and preparation

Deacons of the Deep are at the end of the Cathedral of the Deep. Start from the Cleansing Chapel bonfire and make sure you have opened the lift that returns from the cathedral’s upper route. That lift is the boss-run shortcut; without it, the approach repeats the whole chapel and its giants. Clear enough of the final stairs to reach the fog with your Estus intact, then choose a weapon with a useful horizontal attack. You do not need a crowd-control build, but a wide swing makes room without losing sight of the real target.

Follow the red aura, then interrupt Royce

In the first phase, only the Deacon carrying the red aura takes boss damage. Locate the red glow, enter the crowd from an outer edge, strike that one, and leave as the aura transfers. Do not stay to clear ordinary Deacons after the aura moves. Their candlestick pokes, fireballs, and bodies are designed to stop you reaching the marked target, so each visit needs a route in and a route out. A heavy weapon can use one wide attack to create the lane; a quick weapon can take several hits, but both should leave before the pack closes behind them.

At the phase transition, Archdeacon Royce appears in front of the coffin with larger supporting Deacons. The red aura now identifies Royce, but the threat changes from chasing a moving body to stopping a spell. Watch for the surrounding Deacons raising their candlesticks while Royce lifts his staff: that is the Curse build-up. Walk around the outside to break the cluster’s line, then close in and hit Royce hard enough to interrupt the cast. Do not spend the whole phase killing blue healers or red bodyguards while the Curse orb is building.

Royce also thrusts, slams, and can create a knockback shockwave. When he steps forward with the staff, sidestep and take his flank; when the crowd compresses, retreat to the outside until you can enter on a fresh lane. The second phase is a positional change, not a reason to stand in the crowd for maximum damage. Keep one exit visible, reset after the curse cast, and make every return trip end on Royce rather than the nearest ordinary Deacon.

Reward and next step

The win gives the Small Doll, which is required to pass the barrier into Irithyll of the Boreal Valley later, plus the Soul of the Deacons of the Deep. Keep that soul if you want Ludleth to transpose it into Deep Soul or the Cleric’s Candlestick. The next direct story gate is still reached through the Abyss Watchers and Catacombs, so use Boss Progression to return to the main order rather than searching the Cathedral for an immediate Irithyll path.