I've created this Gun Mage homebrew Fighter subclass. The intent is to make a fighter that can cast spells by engraving them into bullets that they fire. This is inspired by Gun Mages from Iron Kingdoms as released in the D20 creative commons 3.5 rules. And intended for the Spell Jammer setting for D&D 5e
I have adjusted spell progression to be closer to other Subclasses. Included some lore to help with theming interpretation. Spell prep has been adjusted, and spell casting has been adjusted to allow for spell use without multi casing being a problem but without impeding the fighters natural damage output. I have also changed some wording to ensure that most UA/House ruled firearms will be accessible/compatible.
For the full subclass you can check my Gun Mage (revisit): Google Doc
For the previous Build see Gun Mage v1
Gun mages are an obscure sect of militant casters, generally they come from Sorcerer or Rune Carver stock though the rare initiate is born with potential to even the most mundane of families. Once an apprentice is taken by a master they have the knowledge of the arcane art of carving and preparing the single use Arcane Bullets passed on to them, as well as how to create and bond a Magelock firearm. The Gun Mage can only maintain a small number of active bullets at a time as they pull on the Mage's own life force for power. As they grow in skill they can manage more precision in their runes allowing for more bullets and more complicated forms. Each Gun Mage has their own unique style and the life force tied to the bullets ensures no one, not even another Gun Mage can steal or use their Arcane Bullets. While any firearm can be used to fire an Arcane bullet, the arcane energies will foul and damage normal weapons.
Gun Mage Table
Level Prof. Bonus Features 1st 2nd 3rd 4th 5th 3rd +2 Arcane Bullet 3 — — — — 4th +2 3 — — — — 5th +3 3 — — — — 6th +3 3 1 — — — 7th +3 Curve Bullet, Magic Shot 3 2 — — — 8th +3 3 2 — — — 9th +4 3 2 1 — — 10th +4 Elemental Shot 3 3 2 — — 11th +4 3 3 2 — — 12th +4 3 3 2 — — 13th +5 3 3 2 — — 14th +5 3 3 2 1 — 15th +5 Seeking Shot 3 3 2 1 — 16th +5 3 3 2 2 — 17th +6 3 3 2 2 1 18th +6 Caster Shell 3 3 2 2 1 19th +6 3 3 2 2 1 20th +6 3 3 2 2 1
At At 3rd Level you have awakened an arcane heritage and with training to engrave spells into bullets become a Gun Mage.
You gain proficiency with Firearms and Tinkers Tools.
You can craft up to your limit of Arcane Bullets during a long rest, you can maintain a number of bullets containing spell levels as indicated on the Arcane bullet chart. Each Arcane Bullet contains the spell at the spell level it was cast when it is created. All somatic and verbal components are replaced by the Arcane Bullet crafting process. Material components must be present for the crafting of the Arcane Bullet. Crafting Arcane Bullets replaces spell preparation for this class. An unused Arcane Bullet can be scrapped to return its spell slot to the Gun Mage, this does not return consumed material components.
At 3rd Level you learn how to convert a Firearm to a Magelock and bond with it. While any firearm can be used to fire an Arcane Bullet, non-Magelock weapons are damaged and fouled by the arcane energies. (A non Magelock firearm that is used to fire an Arcane bullet becomes fouled and takes damage equal to the spel level of the Arcane Bullet fired. A fouled firearm cannot be fired until an action is used to clear it. Damage can be repaired as normal).
To convert a non-Magelock firearm to a Magelock requires engraving with Tinker's Tools and arcane materials valued at least 250gp. (An enchanted firearm can be converted to a Magelock without disrupting its enchantment) A student is given the materials for their first Magelock by their master when they take up the mantle of Gun Mage.
For all spells the target is the impact point of the bullet when fired and range is the range of the firearm. Spells that have a Spell Attack Roll replace this feature with the Weapon Attack Roll of the firearm being used. Spellcasting DC is equal to 8+Ranged Attack Bonus. The spell replaces the standard weapon damage.
A Gun Mage can bond a number of Magelock Firearms equal to their proficiency bonus.
Spellcasting Stat is Con. For all spells the target is the impact point of the bullet when fired and range is the range of the firearm. Beyond short range, spells with an Attack Roll are at Disadvantage, Spells with a save have Saves against them made at Advantage. Spells that have a Spell Attack Roll replace this feature with the Weapon Attack Roll of the Magelock firearm being used. The spell replaces the standard weapon damage.
Spellcasting DC is equal to 8+Proficiency+Con bonus.
Due to the nature of Gun Mages and Arcane Bullets, the range of an Arcane Bullet is not affected by the Spell Sniper or Sharpshooter feats.
Arcane Bullets are mystically transferred into the firearm by the Gun Mage and are fired as part of an attack action, this ignores the loading and reloading quality of a firearm. Only one Arcane Bullet may be fired in an action regardless of how many attacks that action grants.
At 7th level, you learn how to ensure a missed shot is not wasted, you can mystically curve an Arcane Bullet that has missed its target to another target. When you make an attack roll with an Arcane Bullet and miss, you can use a bonus action to reroll the attack roll against a different target within 60 feet of the original target. You can do this a number of times equal to your Proficiency between long rests.
At 7th level, you gain the ability to infuse your normal bullets with magic as they are fired. Any normal bullet you fire from a Magelock firearm counts as magic for the purpose of overcoming damage resistance.
At 10th level you have learned how to infuse the power of the elements into your normal bullets. You can as a bonus action change the damage type of your Magic Shot to: Fire, Acid, Lightning, Thunder, Cold or Piercing. This change remains until you take a bonus action to change it or take a long rest.
At 15th level you have gained mastery of your Arcane Bullets, you can ignore cover for a target when firing an Arcane Bullet. You can use this ability a number of times equal to your Proficiency Bonus.
At 18th level you are able to craft your Magnum Opus. During a long rest you can craft one Caster Shell. This is an advanced form of the Arcane Bullet. This bullet can be crafted to contain: Circle of Death, Disintegrate, Harm, or Gravity Fissure. This bullet is so volatile that it will disintegrate at the start of your next long rest from the arcane powers contained within. (Gravity Fissure originates at the barrel of the firearm when fired)