Kindred Fang

You gain a +1 bonus to attack rolls and damage rolls made with this magic weapon. This weapon deals Slashing or Necrotic damage (your choice), every time you use it to make an attack.

When you attune to this weapon, you must reduce your maximum number of Hit Dice by 1. The expended vitality swirls around the hilt and forms a shorsword's blade. The blade of this weapon elongates further as it feasts on the blood of your foes. While attuned to this sword, each time you hit a creature with it, its weapon damage die increases by 1 category; for example, a d6 becomes a d8, a d8 becomes a d10, up to a d12. While at an upgraded die category, you may use a Bonus Action to gain the following effects until the end of your turn:

Bloodthirst (d8). You may siphon the blood drawn by this blade to replenish your wounds. When you hit a creature with this weapon, you regain a number of Hit Points equal to the Necrotic damage dealt.

Spread Necrosis (d10). The blood of the blade slithers through the wounds of your enemies to corrupt them. When you hit a creature with this weapon, it cannot regain Hit Points until the end of its next turn.

A Thousand Cuts (d12). The blood of the blade bursts into thin lethal rivulets. When you hit a creature with this weapon, if the result of the attack roll is higher than the Armor Class of any other creatures of your choice within 15 feet of you, those creatures also take damage equal to the damage dealt to the original target. At the end of a turn in which you activate any of these effects, the weapon's damage die resets to a d6.

Vex (Mastery): If you hit a creature with this weapon and deal damage to the creature, you have Advantage on your next attack roll against that creature before the end of your next turn.

Finesse: When making an attack with a Finesse weapon, use your choice of your Strength or Dexterity modifier for the attack and damage rolls. You must use the same modifier for both rolls.

Light: When you take the Attack action on your turn and. attack with a Light weapon, you can make one extra attack as a Bonus Action later on the same turn. That extra attack must be made with a different Light weapon, and you don't add your ability modifier to the extra attack's damage unless that modifier is negative. For example, you can attack with a Shortsword in one hand and a Dagger in the other using the Attack action and a Bonus Action, but you don't add your Strength or Dexterity modifier to the damage roll of the Bonus Action unless that modifier is negative.

Proficiency: martial, shortsword Source: Zamanora: Ballad of the Witch p. 197 (Homebrew)