Hiten Mitsurugi-ryu

You’ve attained mastery in the famed (and fictional) Hiten Mitsurugi-ryū and can deal particularly damaging strikes. In addition to the special attacks, once per turn, when you hit a target with a weapon, you can roll the weapon’s damage dice twice and use either roll against the target. You may use the Attack action, forgoing any Extra Attack, to perform a special attack. 

Ryutsuisen. When you are at least 10 feet above a creature, you can use your action to drop down and make a single, powerful melee weapon attack against it. You make the attack with advantage and on a hit, the attack deals an additional 2d8 force damage and additional 1d8 for every 10 feet you fall on the target. After the attack, whether it hits or misses, you land in an unoccupied space of your choice within 5 feet of the target. You take no falling damage from this drop. You may use this feature a number of times equal to your proficiency bonus and restore expended uses on a long rest.

Ryūkansen. When a creature you can see hits you with a melee attack, you can use your reaction to spin away from the blow and simultaneously counter-attack. You halve the damage of the triggering attack. You can immediately make one melee weapon attack against the creature that attacked you. On a hit, you deal an additional 1d6 force damage. 

Kuzu-ryūsen. As an action on your turn, you can unleash a nine-strike assault against a single creature within your weapon's reach. This attack is too fast to dodge, too powerful to block, and too overwhelming to endure all at once. The target must make three saving throws: a Strength saving throw, a Dexterity saving throw, and a Constitution saving throw. The DC for these saves is equal to 8 + your proficiency bonus + your Dexterity modifier. If the target fails any of the saving throws, the attack connects. It deals your normal weapon damage plus an additional 4d10 force damage. If the target fails two or more of the saving throws, the target is also Stunned until the end of their next turn. Once you use this action, you cannot use it again until you finish a long rest.

Ryūshōsen. You use your free arm to apply force to the back of your weapon and utilize a powerful upward jump during the attack. As an action, you may perform a Long Jump while performing a melee weapon attack provided you spend at least half your maximum movement on the jump. On a successful hit, the attack deals and additional 2d8 force damage. You may land within 10 feet of your original target without provoking an opportunity attack. 

Amakakeru Ryū no Hirameki. You can, as an action on your turn, unleash a decisive strike. Make a single melee weapon attack against a creature within your weapon's reach. On a Hit, the sheer force of your strike connects. The attack deals an additional 2d10 force damage. On a Miss, the velocity of your failed strike creates a powerful vacuum. You can use your reaction to try and capitalize on your opponent's misstep. The target must make a Strength saving throw (DC 8 + your proficiency bonus + your Dexterity modifier). On a failed save, the target is pulled up to 10 feet directly toward you into an unoccupied space. You may then immediately make a second melee weapon attack against them. This second attack is made with advantage, and if it hits, it deals an additional 2d10 force damage. Once you use this action, you cannot use it again until you finish a long rest. On a hit, the attack deals an addition 4d10 force damage. If both attacks miss, you must make a Dexterity saving throw (DC 8 + your proficiency bonus + your Dexterity modifier). On a failed save, you fall prone and take 2d10 force damage. On a successful save, you take 2d10 force damage.