Tearulai

From Waterdeep: Dungeon of the Mad Mage, page 76.

Description
Weapon (longsword), very rare (requires attunement).

The longsword, Tearulai, is a sentient, neutral good Sword of Sharpness with an emerald-colored blade and precious gemstones embedded in its hilt and pommel. The sword's magical properties are suppressed until it is removed from Valdemar's skull.

Evil creatures can't attune to Tearulai; any evil creature that tries to do so takes 20 psychic damage. The weapon's emerald blade can't be damaged or dulled, and the sword can't be teleported anywhere without its wielder while the two are attuned to one another.

Spells. The sword has 6 charges and regains 1d4 + 2 expended charges daily at dawn. A creature attuned to the sword can use an action and expend 1 or more charges to cast one of the following spells from it without material components: Fly (2 charges), Polymorph (3 charges), or Transport via Plants (4 charges).

Sentience. The sword has an Intelligence of 17, a Wisdom of 12, and a Charisma of 20. It has hearing and truesight out to a range of 120 feet. It communicates telepathically with its attuned wielder and can speak, read, and understand Common, Draconic, Elvish, and Sylvan. In addition, the sword can ascertain the true value of any gemstone brought within 5 feet of it.

Personality. Tearulai admires great beauty, music, fine art, and poetry. Vain, the weapon strives to improve its appearance. It craves gemstones and seeks out better ones with which to adorn itself. Most of all, it longs to return to the forests around Myth Drannor, where it was created. If its wielder's goals run counter to its own, Tearulai attempts to take control of its wielder and escape Undermountain, whereupon it can use its Transport via Plants spell to return whence it came.