Demolitionist

Grinning through a gunpowder smeared face, a scrappy goblin hurls an iron-shelled bomb toward a group of astonished kuo-toa--engulfing them in a conflagration of flame amidst a roar of thunder.

Meticulously attaching a glass contraption to a portcullis, a human runs behind cover and snaps his fingers. The arcane runes on the explosive briefly glow before detonating, bathing the iron gate in a sizzling spray of acid that melts the portcullis before your eyes.

A group of cultists cough as a rolling orb spews noxious gas through an enclosed room. Minds clouded, the cultists no longer distinguish friend from foe, and begin plunging their daggers into one another. Behind the door, an elf chuckles as she listens to the screaming cultists tear each other apart.

More technologically minded than other artificers, demolitionists are cunning crafters and wielders of explosives. While a normal bomb is a simple, iron or clay-shelled affair that does a bit of damage in a radius, a bomb crafted by a demolitionist can be flung farther, deal more damage in a wider radius, and can even be infused with magic to increase their utility.

Explosives Expert

When an artificer takes this subclass at 3rd level, you gain proficiency in improvised weapons, the thrown weapon fighting style, and tinker's tools (or another tool proficiency of your choice if you are already proficient with tinker's tools.) The cost and time to craft bombs, gunpowder, and other explosives is halved for you while using tinker's tools. Additionally, a demolitionist artificer can add their INT modifier to the damage rolls of any bombs they utilize.

Demolitionist Spells

Starting at 3rd level, you always have certain spells prepared after you reach particular levels in this class, as shown in the Artillerist Spells table. These spells count as artificer spells for you, but they don’t count against the number of artificer spells you prepare.

3rd Level: entangle, fog cloud

5th level: darkness, shatter

9th Level: enemies abound, fireball

13th Level: confusion, Evard's black tentacles

17th Level: immolation, destructive wave

Demolitionist Bombs

Also at 3rd level, you've learned how to craft demolitionist bombs, a specialized explosive that only demolitionists can create. Whenever you finish a long rest, you can create a number of demolitionist bombs equal to half your artificer level (rounded up) + your Intelligence modifier. These bombs last until the end of your next long rest, whereupon they crumble to worthless ash as your new demolitionist bombs are created. A demolitionist bomb is an improvised thrown weapon, has a range of 40 ft, and deals 2d8 modifier fire damage to all creatures in a 10 ft radius who fail a Dexterity save against your spell DC (halved on success), and deals double damage against structures. You may craft an additional demolitionist bomb by expending 160 gp in materials and two hours of uninterrupted work for each bomb created. Bombs created in this manner remain until used.

Arcane Empowerment

Starting at 5th level, you can infuse the bombs you craft with your spells. As an action, you can cast a 1st level spell or higher that you know and have spell slots for into a demolitionist bomb you've crafted, expending the slot as normal. Instead of immediately taking effect, the spell is infused into the bomb instead. When a demolitionist bomb infused with a spell goes off, creatures in the bomb's blast radius suffer the effects of the spell as well as the spell's damage. You can only concentrate on one spell at a time regardless of whether it comes from an infused bomb or a spell--if you cast a spell requiring concentration or use an infused spell within a bomb that requires concentration, any previous effects requiring concentration immediately end.

- If the spell requires a saving throw to avoid its effect (such as fireball), a saving throw against the spell is rolled separately from the Dexterity saving throw to avoid damage from the bomb. The saving throw against the spell is rolled after the saving throw to avoid the bomb's damage. The range and radius of the spell uses the demolition bomb's range and radius, but the effects and damage from the spell remain the same.

- If the spell requires an attack roll to hit (such as scorching ray), one spell attack roll is rolled against every creature in the bomb's radius, comparing the result to their AC. If the spell attack hits, the creature takes the spell's damage. The attack roll takes place after the Dexterity saving throw prompted by the bomb.

- If the spell creates an effect requiring neither a saving throw nor an attack roll (such as darkness), the effect occurs immediately after the bomb explodes.

While a spell and its associated slot are infused into the bomb, the spell slot cannot be recovered by any means until the bomb is used or is replaced due to taking a long rest. No other types of spell slots--be they Pact Magic slots, spell slots acquired using Sorcery Points, and all other methods of gaining spell slots (such as through magic items) can be used to infuse a bomb--only the Artificer spell slots can infuse a crafted demolition bomb. A spell infused into a bomb in this manner lasts until the bomb is used, the demolitionist creates a new group of bombs after taking a long rest, or the crafter of the bomb dies. Any cheeky attempts to circumvent this restriction will involve the player taking 420d69 screw you damage, seriously limiting their attempt to play D&D in the future.

Improved Detonation

At 9th level, the range, radius, and damage for demolition bombs you create is doubled. (80 ft, 4d8+INT mod fire damage, quadruple damage to structures, 20 ft. radius.)

Additionally, you can choose to delay a demolition bomb's detonation until a more opportune time, instead of exploding on impact. As a bonus action on your turn, you declare that you are delaying the detonation for a number of rounds up to your Intelligence modifier. As an action before the rounds expire, you can trigger any number of delayed bombs within 120 ft of you to detonate. You do not have to see the bombs in order to detonate them, you just have to know where they are. A delayed bomb not within 120 ft of you for any reason (including you being on another plane) detonates after the specified number of rounds expire. Additionally, if you do not remain within 120 ft of the bomb, there is a 25% chance the bomb does not explode and is rendered inert--both magically (allowing the demolitionist to reuse the spell slot) and mundanely.

Explosives Extrordinaire

At 15th level, your skill in crafting and utilizing explosives is second to none. After every long rest, you create a number of demolitionist bombs equal to half your artificer level rounded up + your Intelligence modifier + your proficiency bonus and remain until used. In the same way, you now regain spell slots used to infuse bombs with magic on a long rest. Additionally, you can activate any number of delayed bombs as an action regardless of distance or being on a different plane.