The Brittle King is the Arcana tied to Arthur, a stained-glass knight sealed inside Notre-Dame in Castlevania: Belmont’s Curse. He does not show up as a normal boss door. You trigger him by drawing the sword lodged in stone in the Chapel, and that only works with one specific Arcana equipped.
Quick answer: After you beat Death, go to the Chapel on Notre-Dame’s east side. Equip the Fist of Talos Arcana and interact with the sword in the stone to start the Arthur fight.
Where The Brittle King is in Notre-Dame
Arthur’s room is the Chapel, a district of Notre-Dame in the Dracula’s Castle part of the map. It is on the right-hand side of the cathedral, next to the East Gallery and its Mirror of Life. On the map, the boss marker is a skull labelled The Brittle King.
- Area: Notre-Dame
- District: Chapel
- Route in: through the Transept, then across the East Gallery
- Clue in the room: Feat of Strength
- Secret areas in the Chapel: 2
The East Gallery has spikes and armored enemies, so expect some platforming and air dashes on the way. Once you reach the Chapel, you’ll see an altar with a glowing sword stuck in stone under the stained-glass windows. That sword is Excalibur.
Progress needed before Arthur can be reached
Arthur is a late-game encounter, and the Chapel opens only after a chain of Notre-Dame objectives. You first need access to Notre-Dame itself, which requires completing The Builder, The Occultist, and The Artist. After that, the cathedral’s own progression decides when you can reach the sword.
- Collect the three Melody Sheets of Notre-Dame and play each one at the Giant Organ.
- Purify the corrupted pipes of Notre-Dame, including the Sonata and Concerto.
- Open The Shadow’s door and defeat Death in the Choir.
- Have the Fist of Talos Arcana unlocked from Talos, The Builder.
| Melody Sheet | Location in Notre-Dame |
|---|---|
| Fugue of Notre-Dame | Great Organ Room |
| Sonata of Notre-Dame | Stained Glass Gallery |
| Concerto of Notre-Dame | La Fleche’s attic |
Death’s arena, the Choir, lies in Notre-Dame Undercroft, diagonally north and west of the Mirror of Life. Defeating him also awards Double Jump. The Fist of Talos requirement won’t force you to backtrack: Notre-Dame remains inaccessible until you defeat Talos.
How to pull Excalibur and start The Brittle King fight
The Fists of Talos is a separate Masterpiece fist weapon from the Clock Tower. Equipping that weapon does not free the sword. You need the Fist of Talos spell in an Arcana slot.
Arthur boss stats and attacks
| Stat | Value |
|---|---|
| Health | 11000 |
| Attack | 55 |
| XP | 500 |
| Arcana card |  The Brittle King |
Arthur is a towering stained-glass warrior with a sword and shield. He uses wide sweeping slashes, shield bashes, and overhead strikes that send down beams of light, so keep clear of the light he emits. His size makes him easy to hit from range, and a reach weapon like the Whip lets you deal damage without standing in front of him.
Many status effects won’t work on him. Arthur is immune to bleed, burn, freeze, petrify, launch into the air, slam down, the Chronomantic Dive slow, the Freezing Path link, and the Infernal Pyre launch. Builds that depend on those effects need a different plan for this fight. If you lose, the East Gallery Mirror of Life is next door.
How to confirm The Brittle King is complete
When his health bar runs out, Arthur breaks apart into glass on the Chapel floor. You’ll get the trophy I am Arthur, King of the Britons, and a glowing golden orb is left behind. Strike or absorb the orb to collect the reward. The Brittle King card (Arcana number 13) then appears on screen, followed by a second screen awarding Excalibur.
Stained-Glass Shield spell
The Brittle King’s spell puts a magic shield around Rose. Each attack the shield stops does no damage, doesn’t interrupt her, and carries none of that attack’s side effects. Every block also sends glass shards at nearby enemies. It costs 100 mana and has 30 attack power.
| Works of Mercy | Gift unlocked |
|---|---|
| Survive a fatal hit with the shield | Shield absorbs 1 extra attack |
| Kill 25 Haunted Armor | Glass shard fires whenever Rose takes damage |
| Kill 3 enemies with one attack | 50% less damage when hit mid-attack, no interruption |
The three Works of Mercy are listed next to the three gifts in the same order the game shows them. The shard gift triggers whether or not a shield is active. The mid-attack gift lets Rose finish her attack after taking the hit.
Excalibur two-handed sword
| Stat | Value |
|---|---|
| Rarity / tier | Legendary, tier 4 |
| ATK / attack power | 100 / 44 |
| Stagger power | 30 |
| Mana per hit | 5 |
| Combo finisher | Blade Dive |
Excalibur goes into your inventory automatically when the fight ends. Its attacks fire bolts of light, and holding the attack button before releasing it charges up a stronger strike. If both the Arcana card and the sword have appeared, The Brittle King is complete.
