You gain a +3 bonus to attack and damage rolls made with this magic weapon. In addition, when you use this weapon to make a weapon attack or use any of its charged features to make an attack you ignore any resistance to slashing damage made and ignore immunity to slashing damage treating it instead as resistance to slashing damage. The sword has 10 charges for the following features. These charge features can only be used if you have Yamato's Scabbard in your off-hand. It regains all expended charges after a long rest. If you expend the last charge, roll a d20. On a 20, the staff regains 5 charges.

Able to cast Sword Burst (17th Level) as a bonus action.

Spend 1 charge to target any creature or object within 15 feet of the character that they have line of sight of while wielding this blade in order to cut through space and make a melee weapon attack dealing an extra 1d6 as additional slashing damage. 

Spend 5 charges to cast Steel Wind Strike Dealing magical slashing damage instead of force damage. 

Spend 5 charges to cast Far Step. 

Spend 10 charges to cast Plane Shift but instead of linking hands you slash your sword splitting open in the air a gate that is 60 feet tall and 40 feet wide that eight creatures can pass thru (creature can be unwilling if it is restrained, grappled, and/or pushed in some way into the gate). You can only transport or send a creature to a destination within the lower planes such as the nine hells of tartarus with the use of this spell. If you use this spell to travel to one of the lower planes and use this weapon's feature again to cast the spell, your destination can only be within the same plane you first initially used this spell.  

When you attack a creature that has at least one head with this weapon and roll a 20 on the attack roll, you cut off one of the creature's heads. The creature dies if it can't survive without the lost head. A creature is immune to this effect if it is immune to slashing damage, doesn't have or need a head, has legendary actions, or the GM decides that the creature is too big for its head to be cut off with this weapon. Such a creature instead takes an extra 6d8 slashing damage from the hit.

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

Notes: Bonus: Magic, Damage, Combat, Versatile, Sap