Floor 9: Blackstone Keep

The floor

Floor 9 of the descent

Blackstone Keep lies in the burning march. The deepest floors burn. An ash legion marches through furnaces and cinder fields toward the heart of stone at the bottom. The floor timer runs for 10 minutes; then the Endless Swarm begins and does not stop until you leave through the portal.

Every floor down raises the pressure. On Blackstone Keep monsters have 20.5× the health, deal 6.0× the damage and move 3.2× as fast as on the first floor, and elites appear 2.0× as often. A build that felt safe one floor up needs another damage multiplier here.

Roster

Monsters on this floor

You meet Ashbound, Cinder Skirmisher, Ember Mortar, Slag Brute, Furnace Cultist, Chain Reaver, Sepulcher Knight. Chain Reaver appears here for the first time. The weight says how common each one is in the spawn pool; the minibosses arrive on a fixed clock.

1. From the start
   

   meleeweight 36

   Ashbound

   The old forges burn inside these empty shells.

2. From the start
   

   runnerweight 18

   Cinder Skirmisher

   A brief flare carries it through the ash.

3. From the start
   

   tankweight 14

   Slag Brute

   Failed armor fused around the soldier within.

4. From the start
   

   specialistweight 8

   Ember Mortar

   It hurls smoldering coals from a buried furnace.

5. From the start
   

   specialistweight 8

   Furnace Cultist

   Two offerings feed the flame under the world.

6. From the start
   

   tankweight 8

   Sepulcher Knight

   Its iron salute became a killing stroke.

7. From 1:00
   

   specialistweight 8

   Chain Reaver

   It learned patience in the furnace pits.

8. At 4:00
   

   Miniboss

   Slag Executioner

   The sentence outlived both judge and prisoner.

9. At 8:00
   

   Miniboss

   Furnace Keeper

   It feeds the fire with memories of the living.

Portal boss

The Blackstone Sovereign seals the portal

Portal boss

The Blackstone Sovereign

The final shard beats inside a heart of stone.

Find the portal, interact with it to summon The Blackstone Sovereign and defeat it to open the way down. The The Blackstone Sovereign guide explains its attack and how to dodge it.

Next

Before and after

Up: Floor 8, Ember Wastes. Down: Floor 10, Emberreach. See the whole world and every monster.