SULFUR saint lucia boss guide: how to beat her in the Castle

Fight Saint Lucia in the Castle's throne room: let her reach the middle of the stage and spread her threads, then open fire and keep shooting through her phases. The Castle is the sixth area, entered by completing the Dungeon, and the official SULFUR Wiki's Castle page lists its residents as Riflemen and Assassins — the same assassins Lucia summons during her fight.

Before you enter the throne room

The Castle has four levels with the amulet altar on the third, so charge your amulet before descending. The full walkthrough from Into Indie Games stresses arriving fully stacked on bullets with repair items, because the levels leading up are long and enemies break your gear. Expect gunmen, cultist assassins that leap at you, mine cultists, laser cultists and steam-powered robot enemies. Shoot any mine you hear nearby, and let laser cultists reload before attacking. Cooked food on the dinner tables along the way offers free healing.

1. Enter the throne room on the final level

   Saint Lucia is waiting there. Approach but do not waste ammo yet — she is largely untargetable until positioned.

2. Wait for her threads to spread

   Once she reaches the middle of the stage and spreads her threads across the throne room, start attacking her.

3. Kill the assassins fast

   She summons cultist assassins into the arena. Mines or explosives are extremely effective here — clear them quickly or they will overwhelm you.

4. Survive the ghosts and screams

   Ghosts will chip at you before returning to Lucia; there is little to do about them. Keep damaging her through her scream attacks.

5. Shoot the projectiles in the dark

   When the castle turns dark, immediately shoot the projectiles that appear in the middle of the darkness. Fail and you are set on fire; succeed and Lucia catches fire instead.

6. Repeat until she dies

   Around 50% HP she summons assassins again; at 40% the castle darkens a second time. For the rest of the fight she stays in the middle screaming — out-damage her before your healing runs out. A path to the forest opens on her death.

If the fight goes badly

Players in the Steam discussions recommend never entering a boss arena with your whole savings and relying on a charged amulet to bail out — using it teleports you back to the church, keeping your gear alive for another attempt. Grinding easier areas like the Caves to rank up guns and restock healing is the standard recovery route if you die.

FAQ

Where do I find the Saint Lucia boss?

In the throne room on the final level of the Castle. The Castle is the sixth area and can be entered by completing the Dungeon; its Hedge Maze exit also holds a shortcut that opens after your first visit.

How do I beat the SULFUR saint lucia boss?

Let her spread her threads in the throne room's center, kill her summoned assassins with explosives, and shoot the projectiles in the darkness phases — succeeding sets her on fire instead of you. Then just keep dealing damage through her screams.

What should I bring to the fight?

Plenty of bullets, repair items, healing food and a charged amulet so you can extract to the church if things collapse.

Checked on 2026-11-06 against the official SULFUR Wiki Castle page, the Into Indie Games walkthrough, Steam community discussions and the official Steam store page. The phase percentages and darkness mechanics come from the walkthrough and may shift with patches; exact HP and rewards for Lucia remain unconfirmed.