Hellcastle

The Hellcastle is a structure that generates on world creation, but is only accessible in Hardmode. A small biome generates around the Hellcastle that can be accessed prior to Hardmode. The Library of Knowledge lies at the end of the Hellcastle.

An Underworld Chest will always be in a room adjacent to the entrance. This chest always contains the Boomlash, a chance for Vortex, potions, Impervious Bricks, Ectoplasm, as well as a 10% (1/10) chance for the Vampire Teeth.

In order to enter the Hellcastle, you must craft 2 Impervious Keys using 2 Temple Keys, 10 Ectoplasm, and 1 Earth Stone at a Mythril/Orichalcum/Naquadah Anvil, and unlock both doors at the entrance.

Map image of the Hellcastle

Biome

Impgrass and Brimstone Blocks generate on Ash Blocks in a small area around the Hellcastle. Hell Vines and Resistant Trees grow on the Impgrass.

Library of Knowledge

The Library of Knowledge lies at the end of the Hellcastle. Once inside, there is a Library Altar used to craft the Ectoplasmic Beacon to summon Phantasm.

The Devil's Scythe will spawn on the shelves, as well as many books.

Library of Knowledge

Contents

Characters

• ​Gargoyle
• ​Hellbound Lizard
• ​Phantasm

Unique Treasures

From Underworld Chest:

• ​Boomlash
• ​Ectoplasmic Beacon
• ​Vortex
• ​Vampire Teeth(1/10 chance)

Unique Drops

Through plundering:

• ​Book
• ​Impervious Brick
• ​Impervious Brick Wall
• ​Venom Spike
• ​Resistant Wood Bookcase
• ​Library Altar
• ​Resistant Wood Platform
• ​Devil's Scythe
• ​Underworld Chestneed Underworld Key

From Phantasm:

• ​Ghost in the Machine
• ​Vampire Teeth
• ​Phantom Knives
• ​Ethereal Heart

From vegetation:

• ​Resistant Wood

From terrain:

• ​Brimstone Block

Music

• ​ Dungeon

History

• 11.7: Impgrass, Brimstone Blocks, Hell Vines, and Resistant Trees now generate around the Hellcastle.
• 11.6.2: Changed generation layout. Doors now block entrance instead of Library of Knowledge. Now generates with Venom Spikes instead of Poison Spikes. Bookcases replaced with Resistant Wood Bookcases.
• 11.3: Now spawns with Resistant Wood Platforms instead of Spooky Wood Platforms.
• 11.0: Introduced.

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Surface Layers The Contagion • Tropics
Underground Layers Underground Contagion
Mini-Biomes Dark Matter • Comet
Structures and Other Biomes Hellcastle • Hidden Temple • Ice Shrine • Lava Shrine