Shisui, Water Slasher

Masters of movement and manipulators of momentum, the river ronin were protectors of the waterways. Legend says such samurai could control water with their ki, forming it into shields, whips and whirlpools. These blades, known as the shisui, gave the ronin the ability to conjure water to wield in even the driest deserts or most remote mountaintops.
This weapon has 5 charges and regains expended 1d4 + 1 charges daily at dawn. As an action you can expend one charge to create water, as per the create or destroy water spell.

Weapon (any sword), rare (requires attunement)

Torrent. Using the Attack action, you can expend 1 charge to fire a torrent of water from your blade. If you’re able to make multiple attacks with the Attack action, this effect replaces one of them. You create a 2-foot-wide, 15-foot-long line of high pressure water. Each creature in the area must succeed on a DC 15 Strength saving throw or either be pushed 5 feet back or be knocked prone (your choice).
Jet. As an action, you can expend 2 charges to propel yourself forward in a straight line up to 30 feet long to an unoccupied space you can see. Each creature in a 10-foot-wide line between your origin and your destination must make a DC 15 Dexterity saving throw as high powered jets of water slice into them. A creature takes 4d6 slashing damage on a failed saving throw, or half as much damage on a success.
Uncommon variant: Decrease the DCs to 13. Decrease the distance of Jet to 20 feet and the damage to 2d6.
Very rare variant: Increase the DCs to 16, the range of torrent to a 20-foot-long line, and the damage of Jet to 6d6.