Gunbreaker*

 Gunbreaker is a type of Fighter that wields a gunblade in battle to control the battlefield, while both harming enemies and protecting allies. Gunblades fire bullets into the blade to enhance their cutting power and the force of their strikes. When fired normally, the powder coalesces into a defensive barrier that can protect the wielder and their allies from harm. 

Thanks to Square Enix and Evan (you know who you are) for the inspiration to import this class from Final Fantasy XIV Online into D&D!

Gunblade

Starting at 3rd level, you are able to modify any melee weapon dealing slashing damage and that does not have the Light quality, and make it a Gunblade.
To do so, you have to spend 30gp in raw materials and work on the weapon for at least 1 hour during a Long rest. The weapon must be a weapon you are proficient into, and you are considered proficient in the use of the resulting Gunblade.

A Gunblade is special type of weapon, that combines an especially treated edge with a revolver cylinder and trigger mechanism, and uses specially infused cartridges in order to create special effects in combat.

You are also to create the infused cartridges your Gunblade uses to produce its special effects.
During a short or long rest, you can spend a total of 10gp worth of raw materials and create 2d6 + your Wisdom modifier cartridges. You cannot perform any other action during this a short rest when creating the cartridges, and when doing so during a long rest, you can only eat and sleep for the rest of it.

A Gunblade's cylinder can contain up to 6 infused cartridges. Reloading the cartridges of your Gunblade is an Action; at level 15, Reloading becomes a Bonus Action.

Camouflage: Starting at 3rd level you become proficient in the Stealth Skill.

Cartridge Infused Strikes: Starting at third level when you take this subclass you can learn 2 cartridge infusion options and at higher levels you can learn additional infusions. 2 additional at level 9, 2 additional at level 14 and 2 additional at level 17. Additionally, when you take a level in this class you may swap out any infusions you already know with any other infusion that you meet the level requirements for.

Abdominal Tear

You slash at your targets gut to attempt to slow them down.

When you hit a creature with an attack you can spend one cartridge to force the creature to make a Constitution saving throw DC equal to 8+ proficiency+ WIS modifier or have their movement reduced by 10 feet until the start of your next turn.

Bow Shock

The explosion of your infusion causes lingering damage to all opponents near you

You can expend a cartridge to deal 1d4 necrotic damage to all creatures within 5 feet of you at the start of their next turn. The creatures can make a Constitution saving throw at the end of their turn to attempt to end the effect or make a medicine check DC equal to 8+ proficiency+ WIS modifier to end this effect. On a failure the creature takes the damage again at the start of their turn possibly stacking if struck again with this ability.

Burst Strike

Your strike your target and pull the trigger on your gunblade causing extra damage.

When you hit a creature with an attack you can expend one cartridge to deal an additional 1d8 force damage

Double Down

You raise your gunblade into the air and fire, raining down on your enemies.

You can expend a cartridge to force all creatures in a 15 foot radius within 60 feet of you to make a Constitution saving throw equal to 8+ proficiency+ WIS modifier or take 12d8 radiant damage or half as much on a success.

Eye Gouge

You cause your gunblade to let off a flash of powder in an attempt to blind your enemy.

When you hit with an attack you can expend a cartridge to force the creature to make a Constitution saving throw DC equals 8+ proficiency+ WIS modifier or be blinded for 1 minute. The creature can make a constitution saving throw at the end of each subsequent turn to attempt to end the effect.

Gnashing Fang

You attempt to hook the legs of your enemy to trip them.

When you hit a creature with an attack you can spend a cartridge to force the creature to make a Dexterity saving throw equal to 8+ proficiency+ WIS modifier or be knocked prone.

Heart of Light

Your gunblade lets out a flash of light damaging all enemies and healing all allies within your Royal Guard radius.

You expend a cartridge to force all creatures of your choice within your Royal Guard area to make a Constitution saving throw equal to 8+ proficiency+ WIS modifier taking 5d10 radiant damage, or half as much on a success. Then all allies within your Royal Guard radius take half the damage as healing.

Jugular Rip

You slash violently towards the throat of your opponent attempting to damage their vocal chords.

When you hit a creature with an attack you can expend 1 cartridge to force the creature to make a dexterity saving throw DC equal to 8+ proficiency+ WIS modifier. or become unable to speak for one minute, this rendering spellcaster unable to perform the verbal components of spells.

Lightning Shot

You fire an electrically charged shot off at an enemy.

You make a Ranged attack roll, on a hit the target takes 4d6 lightning damage

Nebula

Your infusion powder coats your body giving you resistance to attacks.

You spend a cartridge to give yourself a +2 bonus to your AC and resistance to bludgeoning, piercing and slashing damage.

Savage Claw

You slash with flair attempting to disarm your opponent.

When you hit a creature with an attack you can spend a cartridge to force the creature to make a Strength saving throw equal to 8+ proficiency +WIS modifier or be disarmed and drop their held weapon.

Sonic Break

The explosion of your infusion causes lingering damage to your opponent.

When you hit with an attack you can expend a cartridge to deal an extra 1d4 damage to your target at the start of their next turn. The creature can make a Constitution saving throw at the end of their turn to attempt to end the effect or make a medicine check DC equal to 8+ proficiency+ WIS modifier to end this effect. On a failure the creature takes the damage again at the start of their turn possibly stacking if struck again with this ability.

Superbolide

You damage yourself in order for your infusion powder to make you invulnerable for a short period.

You strike yourself taking damage from your weapon and gaining a +4 to your AC and immunity to bludgeoning, piercing and slashing damage for 2 rounds.

Wicked Talon

You slash out and attempt to hook your sword around your enemy to stop them from fleeing.

When an enemy within 5 feet of you attempts to leave your range of attack you can use your reaction to spend a cartridge to force the creature to make a Dexterity saving throw equal to 8+ proficiency+ WIS modifier or have their speed reduced to 0 and you move in front of them in the direction they had intended to move.

Royal Guard

Also at third level gain the Royal Guard ability allowing you to engage in a defensive stance providing a distraction to pull you enemies attention away from your allies.

As a bonus action you can force creatures within 30 feet of you to make a Wisdom saving throw causing them to have disadvantage on attack rolls against creatures other than you and cannot move more that 30 feet away from you; if it succeeds than the creature is not affected by this feature for their current turn. Creatures must remake saving throw at beginning of their turn.

If you hit a creature with an attack it has disadvantage on its saving throw to avoid this effect.

Demon Slice

You make a sweeping attack against up to 3 creatures in a 5 foot cone in front of you. Those creatures must make a Dexterity saving throw taking 1d8+ your strength or dexterity modifier of Force damage, or none on a success.

Brutal Shell

The powder generated from this attack bolsters you with vigor.

When you take the second attack action as part of your action you gain a number of temporary hit points equal to five times your proficiency bonus. 

At level 14 you can give the temporary hit points to an ally within 30 feet of you.

At level 18 you can expend a cartridge to add an additional 10 hit points to either you or your chosen ally.

Demon Slaughter

You make a larger sweeping arc attack hitting all creatures within 180 degrees in front of you. 

Creatures within 180 degrees within 5 feet in front of you must make a Dexterity saving throw or take 2d8+ (your strength or dexterity) modifier of Force damage. 

You can increase the range of this attack by 5 feet by expending a cartridge.

Dangerous Divide

You rush forward and leap into the air striking the ground as you land causing an explosion in front of you.

If you move at least 10 feet in any one direction you can then leap into the air moving an additional 10 feet forward and land (as long as there is unoccupied space available) slamming your weapon into the ground, and expending a cartridge, causing an explosion in 5 foot wide by 15 feet long line in front of you dealing 2d8 Thunder and 2d8+ (your strength or dexterity modifier) of force damage.

You can increase the width of the line by 5 feet  for each additional cartridge you expend up to a limit of 4 cartridges. 

The explosion caused by this attack can be heard up to 300 feet away.

Aurora

You gain the ability to cast cure wounds at third level with a range of 30 feet once per short rest. Wisdom is your spellcasting ability for this effect.

At 16th level you can use this ability twice per short rest.

Fated Circle

You make an attack in a circular arc while expending two cartridges hitting all creatures within 10 feet of you. 

All creatures within 10 feet of you must make a Dexterity saving throw or take 2d8 fire and 2d10+ (your Strength or Dexterity modifier) of Force damage.

Continuation

You gain an additional use of your Action Surge ability. Once you use this ability you cannot use it again until you complete a Long Rest.