This thick, leather-bound manuscript has a particularly disgusting decoration—a desiccated tongue nailed to its front cover.

A tome of the stilled tongue is a treasure trove of arcane potential. If you are neutral evil, chaotic evil, lawful evil, or neutral, the book reveals full instructions for creating a lich’s phylactery and offers 500 blank spell pages that function like those in Boccob’s blessed book.

Relic Power: A tome of the stilled tongue also contains directions for eldritch mental exercises designed to strengthen your spellcasting. If you have established the proper divine connection and read the appropriate section of the tome (requiring 1 hour of mental exercises), you can increase your effective caster level for all spells by 1 for 24 hours. However, because the exercises are mystically strenuous, doing them reduces your full normal hit point total by 1 per character level while the caster level increase is in effect. This ability functions once per day.
To use the relic power, you must worship Vecna and either sacrifice a 5th-level divine spell slot or have the True Believer feat and at least 9 HD.

Lore: The grisly cover decoration on the original tome of the stilled tongue once belonged to a former cleric of Vecna who couldn’t keep her order’s secrets. Now five copies are known to exist, but the origins of the other four tongues have never been revealed (Knowledge [religion] DC 20).

Prerequisites: Craft Wondrous Item, Sanctify Relic, Scribe Scroll, secret page.
Cost to Create: 3,500 gp (plus 500 gp for base item), 280 XP, 7 days.