A strange longsword that is hard to look at- the blade hums slightly, occasionally sending out small sparks of purple energy. Its hilt is made of dark, stained wood, covered in intricate runes. When attacking with this blade add your spellcasting modifier in addition to other modifiers. Upon rolling a critical hit, roll on the wild magic table.
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: Versatile, Sap
Wow! This is actually a good item. Well balanced and appropriately powerful for it's rarity.
Good stuff!