LOWER DECKS
The lower decks are riddled with holes, allowing easy
access to the fortress interior. Characters can ascend
to the command deck without needing to make ability
checks simply by moving up through the ruins of the
lower decks, but the wreckage inside the fortress makes
the ascent arduous.BONE WHELKSBone whelks are large mollusks that excrete
an adhesive to attach skulls, bones, and other
detritus to their bodies for protection. These
slugs scour the wreck for organic matter
to feed oo, clinging to torn sections of wall,
floor, and ceiling while taking shelter fromthe searing winds and hungry vrocks. Char-
acters who try to make their way up through
the interior of the wreck are attacked by five
bone whelks (see the accompanying stat
block). Too slow to mount an effective escape,
the bone whelks fight to the death.When a bone whelk dies, it emits a scream that has
a 50 percent chance of attracting the vrocks, which
attack other creatures (including bone whelks) indis-
criminately.SOUL INTAKE
Deep inside the wreck is a 5-foot-diameter, cylindricalpipe made of iron that runs almost the full height of
the fortress. This pipe was designed to siphon tor-
mented souls from the River Styx, feeding them into a
IO-foot-diameter cistern below the command deck topower the fortress. The pipe can be accessed by a hatch
on every deck except the command deck. Nesting inside
the cistern at the top of the pipe is a monster resembling
a 30-foot-long centipede that exudes necrotic sludge. If
it hears one of the hatches open, it slinks down the pipe
to devour any creatures it sees. This creature uses the
remorhaz stat block, with these changes:
- Whenever the monster would deal fire damage, it
deals necrotic damage instead.
• It has immunity to necrotic damage instead of
cold damage.COMMAND DECK FEATURES
The command deck, shown on map 3.6 (page 120).
has the following features:
Iron Surfaces. The floor, walls, ceilings, and doors are
made of iron that has been twisted, bent, and ruptured
in places. Ceilings throughout are 15 feet high.
Light Sources. Areas that a re exposed to the outdoors
are dimly lit by the hellish red sky of Avernus. Beyond
that, the onJy light sources are harmless showers of
sparks that periodically rain down from gashes in
the ceiling.
Sla nt. Like the rest of the fortress, the command deck
leans at a twenty-degree angle, with area W5 being
the lowest part of the deck and area W8 being the
highest. The sloped metal floor is difficult terrain.
BONE WHELK
Large monstrosity, unalignedArmor Class 12 (natural armor)
Hit Points 27 (5d10)
Speed 15 ft., climb 15 ft.STR
10 (+O)DEX
5 (-3)CON
11 (+O)INT
6 (-2)WIS
9 (-1)Senses darkvision 60 ft., passive Perception 9
Languages-
Challenge 1/4 (50 XP)CHA
3 (-4)Adhesive. The bone whelk can cause Medium or smaller
objects to adhere to it. A Medium o r smaller creature that
touches the bone whelk is grappled by it (escape DC 10 ).
Death Scream. When the bone whelk dies, it emits a
blood-curdling shriek than can be heard out to a range of 120
feet. This shriek causes nonmagical, organic material within 10
feet of the bone whelk to rot. Each creature within 10 feet of the
bone whelk when it dies takes 9 (2d8) necrotic damage.Spider Climb. The bone whelk can climb difficult surfaces,
including upside down on ceilings, without needing to make an
ability check.ACTIONS
Bite. Melee Weapon Attack: +2 to hit, reach 5 ft. , one creature.
Hit: 4 (ld8) piercing damage.