When a melee weapon attack hits with this weapon, roll a d4. If the result is a 3 or a 4, the following effect occurs:
Deal 3d8 Lightning damage to the target of your attack, and prevent them from using their Extra Attack or Multi Attack features. This lightning arcs to the any enemies within 5 feet, and marks them with Mark of the Windseeker.
If enemies are within 5 feet of each other when they start their turn and both are marked with Mark of the Windseeker, they become vulnerable to Lightning damage until the end of your next turn.
Proficiency with a Longsword allows you to add your proficiency bonus to the attack roll for any attack you make with it.
This weapon has the following mastery property. To use this property, you must have a feature that lets you use it.
Sap. If you hit a creature with this weapon, that creature has Disadvantage on its next attack roll before the start of your next turn.
Notes: Bonus: Magic, Damage, Combat, Versatile, Sap