Gunbreaker

credit to Lek and xKakarot for the inspiration, and huge credit to Harozuken for the help in fine tuning this subclass :)

A master of gunpowder and martial weapons, Gunbreakers are feared for their cunning and power. Their skill is unmatched by even the fiercest monster. What they lack in pure strength, they make up for in magical prowess. Slinging spells through their Gunbreaker Weapons, allowing a simple attack to become a devastating spell combo.

Gunbreaker Weapon

3rd-level Gunbreaker feature

Starting at 3rd level, you are able to modify any martial weapon that does not have the light quality and make it a Gunbreaker Weapon. To do so, you have to spend 100GP in materials and work on the weapon for at least 1 hour during a long rest using your tinkers tools. Inside the Gunbreaker Weapon contains a Shell Chamber which is used as ammunition for your explosive fencing techniques, and are fueled by your Blast Pool. Your Blast Pool dice are a pool of d4 equal to your proficiency bonus. At level 3 you gain one Shell Chamber, you can add more up to your current proficiency bonus with a successful tinkers tools check(up to DMs discretion). You may use your Gunbreaker Weapon as a spellcasting focus for your artificer spells.

During a short or long rest, you can spend a total of 10GP worth of raw materials to craft a number of Shells equal to half of your artificer level + intelligence modifier. You cannot perform any other action during this short rest when creating the Shells, and when creating Shells during a long rest at least 1 hour must be spent creating them.

Reloading the Shells of your Gunbreaker Weapon costs an Action or one of your Attacks; at level 9, Reloading becomes a Bonus Action.

Explosive Technique

3rd-level Gunbreaker feature 

When you choose this archetype at 3rd level, you learn Techniques that are fueled by special dice called your Blast Pool.

Techniques. You learn two Explosive Techniques of your choice, which are detailed below. These Techniques enhance your attacks in various ways. You can use only one Technique per attack.

You learn additional Techniques of your choice at 5th, 7th, 9th, and 15th level. Each time you learn new Techniques, you can also replace one Technique you know with a different one.

Blast Pool. Your Blast Pool is a number of d4's equal to your proficiency bonus, and when called for you roll the entire pool.

Saving Throws. Some of your Techniques require your target to make a saving throw to resist the Technique's effects. The saving throw DC is equal to your spell save DC.

You may choose Techniques from the following list:

Brutal Shell

3rd-level Explosive Technique

Upon a successful melee attack using your Gunbreaker Weapon, you can consume one Shell to gain Temporary Hit Points in the form of a barrier around you. The amount of Temporary Hit Points is equal to your Blast Pool.

Danger Zone

3rd-level Explosive Technique

Upon a successful melee attack using your Gunbreaker Weapon, you can consume one Shell to cause the target to have disadvantage on any attack not including you as the target until the start of your next turn. In addition, at level 7, If the enemy attempts to attack another target while under this effect, you may use your reaction to attack the creature with a Shell ability.

Demon Slice

Heart of Light

5th-level Explosive Technique

Upon a successful melee attack using your Gunbreaker Weapon, you can consume one Shell to cause you and all allies within 10 feet of you gain a bonus to all saving throws equal to your Intelligence modifier until the end of your next turn.

Heart of Stone

7th-level Explosive Technique

Upon a successful melee attack using your Gunbreaker Weapon, you can consume one Shell to gain a +2 AC bonus until the start of your next turn.

Lightning Shot

3rd-level Explosive Technique

You can utilize a Shell to make a ranged shot using your Gunbreaker Weapon. This ranged strike deals Force damage equal to your Blast Pool + your intelligence modifier and has a range of 30ft.

Low Blow

9th-level Explosive Technique

Upon a successful melee attack using your Gunbreaker Weapon, you can expend one Shell to attempt to knock the target down. If the target is Large or smaller, it must make a Strength saving throw. On a failed save, you knock the target prone.

No mercy

5th-level Explosive Technique

Upon a successful melee attack using your Gunbreaker Weapon, you can consume one Shell to deal additional damage equal to your Blast Pool, and your target is pushed back 10ft.

Rough Divide

15th-level Explosive Technique

Using a Shell from your Gunbreaker Weapon, you can move up to 15 feet towards the target without provoking attacks of opportunity; on a hit, the attack will deal additional damage equal to your Blast Pool.

Sonic Break

7th-level Explosive Technique

When you hit a creature with your Gunbreaker Weapon, you can expend one Shell to attempt to disarm the target using a small targeted explosion, forcing it to drop one item of your choice that it’s holding. The target must make a Strength saving throw. On a failed save, it drops the object you choose. The object lands at its feet.

Gunbreaker Spells

3rd-level Gunbreaker feature 

You always have certain spells prepared after you reach particular levels in this class, as shown in the Gunbreaker Spells table. These spells count as artificer spells for you, but they don’t count against the number of artificer spells you prepare.

ARTIFICER LEVEL	SPELL
3rd	healing word,shield, magic missile
5th	branding smite, spider climb
9th	fireball, counterspell
13th	blight, death ward
17th	hold monster, flame strike

Battle Ready

3rd-level Gunbreaker feature

Your combat training and your experiments with your Gunbreaker Weapon paid off in two ways:

You gain proficiency with martial weapons.

When you attack with your Gunbreaker Weapon, you can use your Intelligence modifier, instead of Strength or Dexterity modifier, for the attack and damage rolls.

Explosive Critical

5th-level Gunbreaker feature

At 5th level, your Gunbreaker Weapon attacks score a critical hit on a roll of 19-20, and cause you to automatically reload a Shell.

You can use this feature once per turn. 

Continuation

5th-level Gunbreaker feature

You can attack twice, rather than once, whenever you take the Attack action on your turn. You can replace one of these attacks with a cantrip.

Nebula

5th-level Gunbreaker feature    

Starting at 5th level, you have learned to manipulate your magic into your armor temporarily, utilizing your bonus action to gain resistance to all damage until the start of your next turn. If any enemy ends its turn within 5ft of you while you are under this effect, you may make an attack of opportunity against that enemy, utilizing a Shell ability if you wish.

Once you use this feature, you can't use it again until you finish a short or long rest.

Shell Expert

9th-level Gunbreaker feature

At 9th level, having gained more experience under pressure, you can now reload your Gunbreaker Weapon with a Bonus Action instead of an Action. Additionally if you use your action to cast a spell using a spell slot, you can use a bonus action to make a single melee attack with your Gunbreaker Weapon utilizing an Explosive Technique if you wish.

Superbolide

9th-level Gunbreaker feature 

When you take damage from a target within 5 feet of you, you can use your reaction and spend any number of loaded Shells and roll your Blast Pool that many times, reduce the damage taken by the result of the rolls. If your roll on your Blast Pool is higher than the damage you would have taken, you can deal the net damage to the creature.

You can use this feature once per long rest. 

Ultimate Explosive Technique

15th-level Gunbreaker feature

Starting at level 15 you can choose one of three Ultimate Explosive Techniques.

Once you use one of these features, you can't use it again until you take a Long Rest.

Double Down

15th-level Ultimate Explosive Technique

Upon a successful melee attack using your Gunbreaker Weapon, you can expend 3 Shells and any creature within a 30 foot cone must make a Dexterity saving throw against your spell DC, or take damage equal to 2 rolls of your Blast Pool, the creature takes half as much on a successful save.

Gunmetal Heart

15th-level Ultimate Explosive Technique

 As a reaction when you or any creature of your choice within 30 feet of you takes damage, you can expend 3 Shells to grant yourself and up to 5 creatures of your choice within 30 feet immunity to that damage until the end of your next turn.

Renzokuken

15th-level Ultimate Explosive Technique

As a bonus action you can expend 2 Shells and perform 2 additional attacks with your Gunbreaker Weapon, these attacks can utilize a Shell ability.