Bal Gnarlnethiltin

This raw ruby gemstone glows like fire attached by a chain of styxym metal to a wicked, thorned handle.

You have a +2 bonus to attack and damage rolls made with this magic weapon.

When you hit with an attack using the flail, the target receives an extra 1d8 fire damage. If the target is of a lawful alignment, they instead take an extra 2d8 force damage.

Flaming Blast. The flail has 4 charges, and regains 1d4 charges at midnight. While holding it, you may use an action to expend 1 or more of its charges to cast fireball at 3rd level (centered on yourself), with each additional charge increasing the level of the spell. You are immune to the damage of this spell when you use this action.

Arcane Absurdity. Bal Gnarlnethiltin is able to grant its wielder expertise in any Intelligence History check once per day. It whispers foreign knowledge to its wielder unbeknownst to even itself as if in a first-hand account. This ability may be used after the roll is made but before determining its success. It regains use of this ability after midnight.

Sentience. Bal Gnarlnethiltin is a sentient chaotic evil weapon with an Intelligence of 12, a Wisdom of 10, and a Charisma of 18. It has hearing and darkvision out to a range of 120 feet. The weapon can speak, read, and understand Common and Abyssal. Its voice is deep and echoing.

Personality. Bal Gnarlnethiltin is facetious, impolite, and perverted. It wishes to annoy all but its wielder with quips and rude remarks. However, it also delights in violence and demonstrating its combat prowess. It wishes to fell stronger and stronger foes to increase its own power. 

Proficiency with a Flail allows you to add your proficiency bonus to the attack roll for any attack you make with it.

Notes: Bonus: Magic, by a creature of non-lawful alignment., Damage, Combat, Sap