Graz'tchar

 is a sentient greatsword with a fragment of the consciousness of Graz'zt, the Demon Prince of Indulgence, and Graz'zt speaks through it from the Abyss. The blade was left behind following the defeat at the Battle of the Umbra Hills, and the weapon now calls out telepathically for a new wielder.

Appearance
Graz'tchar appears to be a noble and kingly: a beautiful, cruciform, silver greatsword inlaid with rubies. It appears to do extra radiant damage to humanoids when activated. A creature with truesight can see its true nature: rusted, pitted, and dripping with acid.

Personality
Graz'tchar's personality is that of Graz'zt, but it pretends to be a wise and sorrowful lost Sovereign of Tal'Dorei, beckoning the wielder to seize their destiny. The sword also attempts to slowly sway the wielder toward sowing chaos in the realm by telling lies about great leaders and claiming that the heads of the Tal'Dorei Council are corrupt and must be overthrown.

Potential wielders of the weapon may have dreams in which they have visions of the sword surrounded by shadows and demons, and hear it whispering pleas for help along with its location.

Background
During the Scattered War, King Neminar Drassig delved into necromancy and entered into dealings with Bane, the evil god of conquest, to fuel his war machine. When Neminar died and his younger brother Trist succeeded him, Bane's patronage continued through the bloodline to Trist. Years later, Zan Tal'Dorei's forces finally backed King Trist Drassig's army into a valley at the base of the Cliffkeep Mountains, but Drassig had a secret weapon. At what would be called the Battle of the Umbra Hills, a flood of fiends poured into the battlefield in support of Drassig.

Both the Critical Role: Tal'Dorei Campaign Setting and the later Tal'Dorei Campaign Setting Reborn include an adventure called "Sword of the Demon Prince" recounting that Graz'zt himself fought in this battle but was defeated and banished to his Abyssal prison, leaving his greatsword Graz'tchar behind.

By the account in the original Tal'Dorei Campaign Setting, a desperate Trist pledged his service to Graz'zt in exchange for the power to smite his foes, and Graz'zt sent his forces to fight alongside Trist's.

By the account in the Tal'Dorei Campaign Setting Reborn, it was Bane who sent fiends to fight alongside Drassig's army, and a clever demon among them gave the blade to Trist, who wielded it until he fell. By this account, the blade was more definitely left alongside Trist's body in the Umbra Hills. Elsewhere in the sourcebook, the sword is also referred to as the "lost blade of Neminar the Black-Fingered", who died years before the Battle of the Umbra Hills.

In both sourcebooks, the sword was left where it lay for centuries. As of the 800s PD, the blade still calls out telepathically across great distances to a warrior in hopes of seducing the wielder into doing Graz'zt's will, and the blade is guarded by demons pretending to be ghosts of great knights.

Features
These are the features laid out in the Tal'Dorei Campaign Setting Reborn, which are slightly changed from those in the original Tal'Dorei Campaign Setting.
 * The wielder gains a +3 bonus to attack and damage rolls with this magic weapon.
 * Corrosive Submission: When Graz'tchar hits a creature with an Intelligence score of 4 or higher, the target takes an additional 3d6 damage (see notes on damage type in Secret features below) and makes a Charisma saving throw (DC 17). On a failure, the target is charmed by the wielder for up to one hour. If the wielder hits the creature again while it is charmed, the additional damage increases to 10d6, the charm ends. On a successful save or when the charm ends, the target cannot be charmed again in this way for 24 hours.
 * Sentience: Graz'tchar has an Intelligence of 14, a Wisdom of 12, and a Charisma of 18. It has hearing and darkvision out to a range of 120 feet. It can speak, read, and understand Common, and communicate telepathically with its wielder. A creature who succeeds on an Insight check (DC 26) while listening to the blade's voice detects the blade's true malicious intent.

Secret features

 * Hidden Nature: The additional damage dealt by this weapon is acid damage but appears to be radiant damage. A true seeing spell or the like reveals the true appearance of the blade.
 * Personality: (See Personality section above.) If the wielder disobeys the urges of Graz'tchar for an extended time, it can attempt to charm the wielder, forcing a Charisma saving throw (DC 17). On a success, they are immune to the sword's charm for 24 hours. On a failure, the wielder is charmed by the sword for 24 hours, and it can force the wielder to make one action of its choice per hour for 24 hours, the wielder accepting this as their own will. If the chosen action leads to the harm of a non-hostile creature or ally, the charm immediately ends. If the wielder succeeds on the saving throw or when the charmed condition ends, the wielder is immune to this property for 24 hours.