In the dark corners of the realm, where chaos reigns and fear lurks, there exists a perilous profession known as the arsonist. These sinister individuals are adept at turning the deadliest of weapons, firearms, into instruments of fiery destruction. With a malevolent skill honed through dark arts or twisted science, they transform ordinary firearms into flamethrower variants, spewing forth torrents of scorching flames upon their enemies.

Moth to a Flame

Beginning when you choose this speciality at 3rd level, you have a natural inclination towards destruction and weaponry. You gain proficiency with Firearms and Smith's Tools. If you already have this proficiency, you gain proficiency with another type of artisan’s tools of your choice.

Arsonist Spells

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

Arsonist Spells

Fire Starter

Also at 3rd level, your thirst for chaos drives you to enhance your weaponry, turning a regular firearm into a tool of devastation. Over the course of a long rest, you can convert a nonmagical firearm into a fiery variant. The weapon receives a number of changes and benefits, listed below:

• The firearm now deals fire damage, instead of its usual damage type.
• When you attack with this firearm, you can use your Intelligence modifier, instead of Strength or Dexterity, for the attack and damage rolls.
• The firearm can ignite any flammable objects it hits that aren't being worn or carried.
• The firearm can be imbued with appropriate infusions like a regular firearm.
• The firearm can act as an arcane focus for your artificer spells.

Consuming Conflagration

Finally for 3rd level, you can enhance the potency of your flames. When you deal fire damage to a creature, you can magically intensify the flames, setting them on fire. The creature must make a Constitution saving throw against your spell save DC or be set ablaze, taking 1d6 fire damage at the start of each of their turns. They must make the saving throw again at the end of each turn, ending the effect on a success. A creature not on fire can use their action to extinguish the flames. The damage of this ability increases to 2d6 at 8th level, 3d6 at 14th level, and 4d6 at 20th level.

You can use this ability an amount of times equal to your proficiency bonus per long rest.

Barrage of Embers

At 5th level, your thirst for chaos drives you to commit even more acts of violence. You can attack twice, rather than once, whenever you take the Attack action on your turn.

In addition, your constant exposure to flame has enured you to the heat. You are now resistant to fire damage, and you don’t suffer the effects of extreme heat.

Reduced to Ashes

At 9th level, your flames burn brighter and hotter, searing even the toughest of flesh. Fire damage you deal ignores resistance to fire damage, and treats immunity as resistance instead. If fire damage you deal kills a target, you can choose to turn them to a pile of ashes. You can dismiss any nonmagical flames within 30 feet of you as an action, or any of your magical flames.

In addition, the fire you covet can pull you back from the brink of death. When you are reduced to 0 hit points but not killed outright, a fiery explosion will tear from your body. Hostile creatures within 10 feet of you must make a Constitution saving throw, taking 3d8 fire damage on a failed save, and half damage on a successful one. They must then make a second Constitution saving throw, and if they fail they are set ablaze, as though they were targeted by your Consuming Conflagration ability. After this explosion, you regain hit points equal to the 3d8 fire damage dealt.

Once you use this ability, you cannot do so again until you complete a long rest.

Bringer of Doom

At 15th level, your bond with fire and your love for bedlam devour you, turning you into an unnatural creature of chaos and cinders. You are now immune to fire damage and effects that would turn you to ash, such as the Disintegrate spell. You can breathe normally in any environment, and you have advantage on saving throws made against harmful gases and vapors (such as Cloudkill and Stinking Cloud effects, inhaled poisons, and the breath weapons of some dragons).

In addition, your flames are so eager they can seek out more foes to burn. When you deal fire damage to a creature, you can use your reaction to cause another creature within 5 feet of them to make a Constitution saving throw. If they fail, they take half the original damage (rounded down) and take no damage on a success.

You can use this ability an amount of times equal to your Intelligence modifier per long rest.