Avenged Blade

 

You gain a +3 to attack and damage rolls made with this magic weapon. 

The Tempest's Will: When you hit a creature with this weapon, that target takes an extra 1d8 lightning damage. If you are in the midst of a storm during combat, that damage increases to 2d8.

This item has up to 4 charges. You can use an action to expend 1 of its charges to cast one of the following spells at 3rd level, ignoring the component requirements of the spells

• Lightning Bolt
• Tidal wave (Xanathar's Guide to Everything, Page 168)

You can also spend a charge to use the Lightning Step special ability (outlined below)

The save DC for these spells is 17.

 

Lightning Step: Your body becomes lightning, and you are able to teleport to a location you can see within 200 feet. When you reappear, all creatures within 30 feet of you take 3d8 lightning damage (no saving throw)

 

The Ocean's Call: You can briefly summon Umberlee's power to serve you in a moment of need. As an action, select a point within 120 feet of you. At that point, Umberlee's wrath falls on any creature in a 15 foot radius column, stretching up 300 feet in the air. All creatures in that area must succeed on a DC 17 Dexterity saving throw or take 18d6 lightning damage and 18d6 force damage, or half on a successful save. 

After using this ability, roll a d100. On a 0-95, the sword vanishes from this and all planes of existence. It cannot be reclaimed by any means including use of the Wish spell. On a 96-100, the sword remains, and you instantly regain the use of The Ocean's Call ability.

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

Notes: Damage: Lightning, Bonus: Melee Weapon Attacks, Finesse, Vex