Descent into Avernus

Unless immune to the river's effects, a creature that

drinks from the Styx or e nters the river is targeted by a

feeblemind spell (save DC 20). A creature must repeat

the saving throw whe never it starts its turn in the river,

until it fails the save. A feebleminded creature can drink

from the Styx and swim in its waters without suffering
any additional deleterious effects.
If a c reature fails its saving throw a nd remains unde r

the spell's effect for 30 consecutive days, the effect be-

comes permanent (no save) and the creature loses all its

memories, becoming a near-mindless shell of its former

self. At that point, nothing s hort of a wish spell or divine

intervention can undo the effect.

Water take n from the River Styx loses its potency af-

ter 24 hours, becoming a ha rmless, foul-tasting liquid.

However, arcanaloths, night hags, and other fell crea-

tures might know rituals that can prolong the wate r's

potency, at your discretion.

ALTERATIONS TO MAGIC

Avernus is the entrance to the Nine Hells, a battlefield

drenched in eldritch energy. The magic of the Weave

works diffe rently here, manifesting in unusual ways.

COSMETIC SPELL MODIFICATIONS

At your discretion, a spell can be modified cosmetically

to enhance the corrupting nature of Avernus. Here are

some examples:

Bigby's Hand. T he conjured hand is a fie ndish claw.

Find Familiar. The familiar i s an imp.

Find Steed. The steed is a nightmare.

Find the Path. An imp appears and begrudgingly guides

the caste r to the desired location while compJajning

the whole time, disappearing when the destination is

reached or the spell e nds.

Fog Cloud. Moaning faces appear and fade in the yellow

fog that smells like s ulfur.

H ellish Rebuke. The cackling of imps accompanies the

fire unleashed by this spell.

Mage Hand. The summoned hand is shaped like a claw.

Rary's Telepathic Bond. Characters linked together by

the spell can hear vague, infernal whispering in the

background, but can't make out what's being said.

TELEPATHIC COMMUNICATIONS

Archdevils can eavesdrop on communication spells

s uc h as message and sending sent from or within the

Nine Hells. Because of this, those engaging in telepathic

communication a lways have the feeling that t hey are

being listened in on or watched by some infernal pres-

e nce, even if an a rc hdevil isn't eavesdropping on their

communication.

Telepathic communications via magic items such as

sending stones or a helm of telepathy can be overheard

by an a rchdevil as well. Communicating with a serpen-

tine owl, an orb of dragon kind, or a sentient weapon

also runs the ris k of being overheard in Avernus. Rings

of mind shielding work the same in Avernus as they

do on any other plane and are highly valuable items in

the Nine Hells, coveted by all fiends to avoid the prying

minds of their masters.