This black-bladed dagger has a wavy blade and a hilt set with a chunk of fool’s gold.

When you wield this weapon, it functions as a +1 unholy dagger. Unlike most relics, a dagger of denial functions for a wielder of any alignment, and it retains its sentience and basic relic powers even if you don’t establish the proper divine connection, though it will not reveal its intelligence to you or use any relic powers on your behalf. However, if you aren’t neutral, lawful evil, neutral evil, or chaotic evil, the dagger betrays you at the first available opportunity. A dagger of denial starts working against you by surreptitiously dispelling your spells and those of your allies, leaving you without the magic you depend on for battle.

Relic Power: If you have established the proper divine connection, a dagger of denial reveals its intelligence and sentience (AL NE; Int 18, Wis 10, Cha 18; speech, telepathy, darkvision 120 ft., blindsense, hearing, Intimidate 10 ranks for a total modifier of +13, Spellcraft 10 ranks for a total modifier of +14, Bluff 10 ranks for a total modifier of +14, Ego score 26). In addition, the dagger can use detect magic at will and greater dispel magic once per day.
To use the relic power, you must worship Vecna and either sacrifice a 6th-level divine spell slot or have the True Believer feat and at least 11 HD. If you sacrifice an 8th-level divine spell slot (or you have the True Believer feat and at least 15 HD), the dagger grants you a continuous detect scrying effect and can use arcane eye once per day.
A dagger of denial takes great glee in disrupting other spellcasters. It giggles and cackles to you constantly when facing enemy spellcasters. It generally readies an action to counterspell such a foe’s spellcasting with greater dispel magic.

Lore: The four daggers of denial known to exist were originally gifts from Vecna to the wizards he charged with keeping his priests in line (Knowledge [religion] DC 20).

Prerequisites: Craft Magic Arms and Armor, Sanctify Relic, arcane eye, detect magic, detect scrying, greater dispel magic.
Cost to Create: 10,000 gp (plus 302 gp for base item), 800 XP, 20 days.