Way of the Hunter's Longsword

Having moderately high attack power combined with mobility means having some drawbacks, however. Since its departure from the Great Sword family, the Long Sword has no ability to guard against attacks by any means, aside from the standard dodge rolls. Thus, the hunter must be aggressive enough to know when and where to attack, while being cautious enough to know when to cease attacks and dodge. The Long Sword has a short delay after most attacks, but balances this with a back-hop/wide swing attack (known officially as the "Fade Slash") which can be performed after any attack, allowing fluidity. The hunter must take some risks, in order to fill up their Spirit Gauge, which, once full, increases damage dealt and enables the sword to unleash a powerful Spirit Combo: an easy way to slice up any monster you wish to hunt. 

Level 3: Spirit Longsword Technique

As a practitioner of the long and mighty longsword, you have proficiency with longswords and katanas, and in your grip, their reach is, at minimum 10ft. These weapons count for your monk features that would normally impact unarmed strikes, with the exception of flurry of blows (which you will gain at higher levels). When you make an attack with one of these weapons, you may select a swing style,  and if you hit with that attack style, it contributes towards your Spirit Gauge. The gauge has a maximum capacity equal to your proficiency bonus x2, and each successful hit fills it an amount equal to your wisdom modifier. Whenever it is full, you may use charges from it until it is empty again (even if you are short an an ability, such as one that costs 3, but you have 2 remaining, you may use the final amount to activate it) with swing styles that expend spirit gauge charges. Once fully depleted, the gauge upgrades by one level, to 2 for the remainder of the combat, and can be upgraded to a maximum of level 3. Some spirit gauge spending abilities will reference these upgrade levels, and become stronger as a result. The first two swing styles are detailed below:

Vertical Slash: You swing your blade down in a perfect arc. This attack has 5 additional feet of reach at targets that are above you.

Focus Thrust: You thrust your blade, dealing piercing damage instead of slashing damage. 

Fade Away Slash: You swing your blade, expending up to 3 on your spirit gauge. For each charge expended, you may move backwards from the target you attacked 5ft, without taking attacks of opportunity. 

Iai Slash: You may sheathe your sword as an item interaction to enter a reactionary state, capable of using this attack. While using it, you may use your extra attack feature with any readied actions to attack you may take. 

Level 6: Foresight Slash

While your sword is sheathed and you've taken a ready action to attack, you may use a bonus action and expend 5 spirit gauge charges to improve that ready action into a Foresight Slash. Instead of simply making your attacks, you may use them in reaction to another creature taking the attack action against you. Make your attacks as normal, and then, for each attack made this way, reduce the damage of one of the attacks made against you by your attack roll's damage, ignoring extra bonuses from external sources like spells and additional dice from magical effects. (Example. Whilst fighting a bear, you use this feature. When it takes the attack action against you, you use your reaction to attack it twice, rolling 1d8+5 for damage. If both of it's claw attacks land, their damage would be reduced by that 1d8+5 damage roll, but not by a bonus from something like eldritch claw tattoo or divine smite).

While making this attack, you may also choose to move up to your movement speed closer to the enemy making attacks against you before making your attacks. Doing so expends 1 extra spirit gauge for every 10ft you move this way.

Level 11: Helmbreaker

When you take the thrust attack option, if your spirit gauge is at least level 2, you may transition it into an acrobatic helmbreaker attack (finish your initial attack before initiating it). Expend any amount of spirit gauge charges (min 1). Make an acrobatics check, with a DC equal to your attack roll. On a success, you bound into the air, falling down with a rain of slashes upon the creature you attacked. Roll an amount of d4s equal to the acrobatics check, dealing that much slashing damage to the creature, plus an additional amount of d6s equal to the amount of spirit gauge charges expended to use this attack. After you use this ability, you cannot make any additional attacks until the end of the current turn, and your spirit gauge level becomes 1 lower. 

Level 17: Longsword Master Flow

You become the embodiment of the flowing river, gaining the ability to transition all of your longsword techniques into one ultimate technique. This can only be used if your spirit gauge is full and at level 3, and can only be used twice per long rest. The gauge empties, and you unleash a combo of attacks, in the following order:

Vertical Slash - Fade Away Slash - Iai Slash (Foresight Slash, using movement) -  Thrust Attack - Helmbreaker - Forest of Strikes

Forest of Strikes: You make a number of attacks, split as evenly as possible between every creature within your reach equal to your wisdom modifier