Gunbreaker

.Gunbreakers are masters of defence, even able to goad enemies when attacking them. They can also accumulate Powder Gauge Cartridges to add explosive blasts to their attacks. Skilled Gunbreakers can reduce their damage taken, and masters can even gain invulnerability.

Gunbreakers are one of the classes capable of accumulating and manipulating residual aether to unleash powerful Limit Break spells. The have access to Shield Wall, Mighty Wall and Gunmetal Soul.

Gunbreakers are able to activate an ability called 'Royal Guard', which causes enemies they hit to possibly be goaded. They can also accumulate 'Powder Gauge Cartridges' with every 3rd melee weapon attack, which can be used to add an explosive blast to a melee weapon attack. They can store up to 2 Powder Gauge Cartridges at a time.

Starting at level 7, Gunbreakers are able to summon defensive and regenerative aether when they attack. Every time a 7th level Gunbreaker makes their second melee weapon attack in the same action, they can gain temporary hit points and heal themselves; the temporary hit points last for 5 rounds.

Starting at 10th level, Gunbreakers gain the ability to charge at an enemy within 30 feet with a bonus action, without using movement speed. This can be done once every 30 seconds, with a max of 2 usages being able to be accumulated at one time.

Upon reaching levels 15, Gunbreakers gain a mastery over their Powder Gauge. They are able to hold a 3rd Powder Gauge Cartridge, their explosive blasts do increased damage, and they can use a bonus action after using a Powder Gauge Cartridge to generate an additional explosion from the smoke and fumes leftover.

Gunbreakers that reach level 18 have a mastery over defensive aether. Once per short rest, they can use 'Superbolide', sacrificing HP equal to half their max in order to gain complete invulnerability for 3 rounds.

Based on the Gunbreaker class from FFXIV

Level 3: Royal Guard

As a free action, you can apply 'Royal Guard' to yourself. When applied with 'Royal Guard', creatures you hit must make a DC 15 WIS saving throw, or be goaded. Goaded creatures can only target the creature that goaded them when using offensive actions.

Level 3: Powder Gauge

Your every 3rd melee weapon attack will grant you one 'Cartridge', which is added to your 'Powder Gauge'. The Powder Gauge can have a maximum of 2 Cartridges. Upon reaching levels 14, the max amount of Powder Gauge Cartridge limit is increased to 3. Whenever you make a melee weapon attack, you can use one Powder Gauge Cartridge to deal an additional 2d6 fire damage. Whenever you use a Powder Gauge Cartridge, that weapon attack does not count towards the 3 melee weapon attacks to gain a Powder Gauge Cartridge.

Level 7: Brutal Shell

Whenever you make your second melee weapon attack within the same action, you are healed for 3d4, and gain temporary hit points equal to the amount healed. These temporary hit points last for 5 rounds.

Level 10: Trajectory

Starting at level 10, you gain 1 use of 'Trajectory' every 5 rounds (max 2 usages stored). 'Trajectory' is a bonus action that charges an enemy within 30 feet. The target must make a DC 15 WIS saving throw, or be goaded for 1 round. Goaded creatures can only target the creature that goaded them when using offensive actions.

Level 15: Continuation

Starting at level 15, whenever you use a 'Powder Gauge Cartridge', you can use the remnant smoke and powder to make an additional flaming attack. After consuming a Powder Gauge Cartridge, you can use a bonus action that turn to ignite the residual powder and smoke, dealing an additional 2d6 fire damage to the target. Additionally, your extra fire damage from using Powder Gauge Cartridges is increased from 3d4 to 5d6.

Level 18: Superbolide

Starting at 18th level, you gain the ability to summon powerful defensive aether. Once per short rest, you can use Superbolide. Superbolide deals damage to you equal to half your max HP, but gives you immunity to all damage types and conditions for 2 rounds.