A Plaguesmith is an Artificer that focuses on the infectious arts. Through meticulous study or by bad luck and circumstances, you are very familiar with diseases and the disease process. A Plaguesmith's understanding of infections is so exceptional, they can craft a bespoke plague that can harm others but leave the Plaguesmith unscathed.
Epidemiological Proficiencies
When you adopt this path at 3rd level, you gain proficiency with either a healer's kit or poisoner's kit. Additionally, you have advantage on skill checks related to diagnosing and treating infections.
Plaguesmith Spells
You always have certain spells prepared after you reach particular levels in this class, as shown in the table below. These spells count as artificer spells for you, but they don’t count against the number of artificer spells you prepare.
| Artificer level | Plaguesmith Spells |
|---|---|
| 3rd | detect poison and disease, ray of sickness |
| 5th | lesser restoration, wither and bloom |
| 9th | dispel magic, spirit guardians (necrotic only) |
| 13th | aura of purity, blight |
| 17th | contagion, mass cure wounds |
Plague Bearer
When you specialize into Plaguesmith at 3rd level, you may infect yourself with a magical disease, spreading toxic death! You can use 10 minutes to craft a special plague and fill a syringe or vial. The creation of this disease requires a healer's kit or poisoner's kit and you may have a maximum number of doses equal to your proficiency bonus.
Any doses last either until taken or the end of your next long rest. As an action you may inject or ingest a dose of this magical plague, becoming Infected for 10 minutes.
While Infected, any creature that deals you damage within 5 feet of you must, as your noxious bodily fluids spray onto them, succeed on a Constitution saving throw or take necrotic damage equal to half your artificer level. A creature harmed by your plague in this way cannot be harmed by it again until the start of their next turn.
Vicious Virulence
Also at 3rd level, while Infected, you may use your disease-riddled body to harm others. As a bonus action, you may use your bodily fluids to inoculate a weapon or piece of ammo; when you attack with an inoculated item, you can use your Intelligence modifier, instead of Strength or Dexterity, for the attack and damage rolls. This inoculation lasts until the start of your next turn.
The first creature hit with your inoculated item takes extra necrotic damage equal to 1d6 plus half your artificer level and must succeed on a Constitution saving throw or become infected by your magical plague until the end of their next turn. An infected creature subtracts 1d4 from the first ability check, attack roll, damage roll, and saving throw, if any are rolled, that creature makes while infected.
The die subtracted when a creature is infected changes when you reach certain levels in this class, becoming a d6 at 5th level, a d8 at 9th level, and a d10 at 15th level.
Individualized Infection
The Infection, a magically necrotic effluvium, is excreted from your bodily fluids: your blood, pus, saliva, sweat, and tears. You are immune to the damaging effects of your own plague but look noticeably ill and repulsive while Infected. If another creature besides you takes a full dosage of your concocted disease, they must succeed on a Constitution saving throw or suffer one level of exhaustion.
Rat-licker
At 5th level, you have advantage on saving throws against being poisoned; additionally, once on each of your turns while Infected, you may either ignore a creature's resistance to necrotic or poison damage, deal half damage to a creature that is immune to necrotic or poison damage, or make an extra weapon attack when taking the attack action.
Routes of Transmission
At 9th level, you may choose whether or not to suffer the symptoms of any disease you are infected by.
Additionally, your terrible toxins become more virulent. Once on each of your turns, when a creature takes necrotic damage from you, choose up to three creatures within 15 feet of the original creature that are not behind full cover; those additional creatures take necrotic damage equal to proficiency bonus.
Master of Maladies
By 15th level, your knowledge and prowess regarding organic compounds is thorough and expansive, granting you new capabilities:
Vaccinated: You cannot be poisoned and you gain resistance to necrotic and poison damage.
Airborne: The range of creatures affected by your plague when you are attacked increases from 5 feet to 15 feet.
Master Plaguesmith: You may either cast harm or heal once per long rest without expending a spell slot. The range for these spells when cast using this feature is touch.
