Weapon (rifle, automatic), unknown rarity (requires attunement by a creature. While attuned, the sentient light machine gun is more cooperative. However it will judge your soul.)
Weapon Type: Heavy Ranged Weapon (Firearm, requires ammunition)
Damage: 1d10 force + 1d10 piercing
Range: 30-foot cone/600ft (see Cone of Fire and Deadeye Shot)
Weight: 42 lbs.
Ammunition: Arcane Essence Crystals or Bullets (see Ammunition Versatility)
Capacity: 100 rounds per magazine
Attunement: Requires 2 attunement slots—one for the Arcanum Cataclysm, one for Arcane Essence Crystals
Strength Requirement and Limitations (If Not Attuned): If you are not attuned to the Arcanum Cataclysm, you must have a Strength score of at least 15 to wield the weapon. If your Strength is lower, you cannot carry it at all. While not attuned, you suffer disadvantage on all checks and attack rolls using this weapon, your movement speed is halved while wielding it, the weapon's base damage is halved, and you do not gain any benefits or features that require attunement.
Heavy Weapon: Requires two hands to wield.
Loading: Use an action to reload the magazine.
Bulky: Disadvantage on Stealth checks.
Description
This rune-etched, obsidian-chassis firearm gleams with shifting glyphs and radiates raw magical energy. The Arcanum Cataclysm is a two-handed, fully automatic heavy weapon of mythic power—its frame reinforced by ancient enchantments and stabilized by a gyrostabilizer harness, allowing even lightly armored heroes to wield its tremendous force. When unleashed, the Cataclysm roars with a thunderous volley of arcane projectiles, leaving devastation in its wake. Ingeniously, this weapon is the ultimate fusion of black powder and arcane brilliance, forging an armament of legend and innovation that transforms the tide of battle.
Equipped with a 100-round magazine, the Cataclysm ensures sustained magical barrages. Its runic grip and balanced design provide remarkable control, even amidst the chaos of battle.
The rune-inscribed barrel channels magical force for unerring accuracy. Masterwork attachments—unlocked through heroic deeds—allow the Cataclysm to be customized to suit any adventurer’s strategy.
A favorite of arcane tacticians, the Cataclysm is as effective in close quarters as at range. Its flexibility and raw power are whispered of in taverns and war councils alike.
When fired, the Cataclysm’s thunderous report heralds ruin for its foes, shattering barriers and sending enemies fleeing. Throughout the realms, it is coveted by warriors, artificers, and scholars as a symbol of ultimate power and arcane ingenuity.
Weapon Properties
Ammunition Versatility. The Arcanum Cataclysm can be loaded with either mundane bullets or Arcane Essence Crystals. When loaded with bullets, the weapon deals only half its normal damage. When loaded with crystals, it deals full damage and expends ammunition per attack (see below for crystal details). Reloading the magazine requires an action.
Cone of Fire. As an action, you make a single ranged weapon attack roll with this weapon, using your Dexterity modifier and proficiency bonus. Compare the result to the AC of each creature or object within a 30-foot cone originating from you. On a hit, a target takes 1d10 force and 1d10 piercing damage. Each attack expends 3 crystals or bullets.
Mythic Enhancement. The Arcanum Cataclysm grants a +3 bonus to attack and damage rolls made with it.
Misfire. If you roll a natural 1 on an attack roll with this weapon, it misfires, dealing half the attack’s damage to you or an ally (ignoring resistances).
Bulky. While wielding this weapon, you have disadvantage on Dexterity (Stealth) checks.
Heavy Weapon. This weapon requires two hands to wield.
Loading. After making attacks with this weapon on your turn, you must use an action on your next turn to reload before you can attack with it again.
Melee Bash. As a bonus action while wielding the Arcanum Cataclysm, you can make a melee weapon attack against a creature within 5 feet. On a hit, the target takes 2d6 bludgeoning damage plus your Strength modifier. If you roll a natural 1 on this attack, the weapon cannot be used for any attacks until you spend an action using tinker's tools to recalibrate the mechanism.
Aiming. By taking your time and lining up a shot, you are able to increase your accuracy with ranged attacks. You may use your action to aim. While aiming, you cannot move or make an attack this turn. If you do, you gain an advantage on your next ranged attack roll.
Attunement Features
While attuned to both the Arcanum Cataclysm and a set of Arcane Essence Crystals, you gain the following benefits and abilities:
Gyrostabilizer
The magical harness, imbued with strength enchantments, allows you to easily heft, aim, and operate the weapon without fault. While wearing the harness, you cannot be disarmed of this weapon; if an attempt is made, the weapon simply dangles by the harness, still attached to you. In addition to its other features, the gyrostabilizer harness increases your carrying capacity by 50 lbs. due to its reinforced frame and load-distributing design. If you are not attuned, the weapon is extremely unwieldy, imposing disadvantage on all checks and attacks made with it, and halving your movement speed while wielding it.
Deadeye Shot
As a bonus action, you can make a precise shot at one target you can see within 600 feet. On a hit, the target takes 2d12 piercing damage. This attack expends 8 crystals and can be used a number of times equal to your proficiency bonus per long rest.
Arcane Overcharge
As an action, you can infuse the Arcanum Cataclysm with volatile arcane energy. On your next turn, your next attack with this weapon deals 4d10 force damage on a hit (expends 15 crystals).
Arcane Disruption
As an action, you unleash a torrent of arcane energy in a 30-foot cone. Each creature in the area must make a Dexterity saving throw (DC = 8 + your proficiency bonus + your Dexterity modifier). On a failed save, a creature takes 4d12 radiant damage. On a successful save, a creature absorbs the arcane energy and heals for the rolled damage. (Expends 30 crystals.)
Stronghold Defense
While wielding this weapon, your Armor Class increases by 2.
Cover Fire
When you take the Cover Fire action, your AC increases by 4 until the start of your next turn, and attack rolls against you and your allies within the cone are made with disadvantage. Additionally, any creature in the cone cannot move until the start of your next turn. At the start of your next turn, the gun overheats (see Weapon Stability) and cannot be used until you spend an action to cool it down (you must skip using the weapon for one turn). If you run out of crystals during Cover Fire, the action ends immediately, and you must spend an action to reload. Reloading also cools down the weapon, allowing you to use it again on your following turn.
Close Quarters Combat
While wielding the Arcanum Cataclysm, you do not have disadvantage on ranged attack rolls made while within 5 feet of a hostile creature. In addition, your ranged attacks with this weapon ignore half cover and three-quarters cover against targets within 30 feet. You also gain a +1 bonus to attack rolls made with this weapon, which can be further increased through mythical enhancement.
Attachment Mastery
(Prerequisite: Attunement to the Arcanum Cataclysm) You have mastered the art of modifying your weapon with arcane attachments, enhancing its versatility and power. You can equip all 8 attachment slots of your choice to the Arcanum Cataclysm. You cannot equip more than one of the same attachment at a time. For equipping or swapping attachments, see the tactical enhancement section.
- Each attachment confers unique benefits or alters the weapon’s properties. Some may have additional prerequisites or require separate attunement (see Attachments section).
- The effects of attachments only function while the Arcanum Cataclysm remains attuned to you.
- If you lose attunement or unequip an attachment, its benefits immediately end.
Weapon Stability
Whenever you use Arcane Overcharge or Arcane Disruption, you must test the weapon’s stability.
Jamming
After each consecutive use of Arcane Overcharge or Arcane Disruption without cleaning the weapon, roll a d4. The DC to avoid a jam increases by 1 with each use:
- First use: weapon jams on a roll of 1
- Second use: weapon jams on a roll of 1–2
- Third use: weapon jams on a roll of 1–3
If the weapon jams, it cannot be used again until repaired (an action), and you lose your next action.
Explosion
After the third stability check, each subsequent check requires you to roll a d6. On an odd result, the check succeeds. On an even result, the weapon explodes and is destroyed. You and all creatures within 10 feet take double the weapon’s base damage (4d10 force and 4d10 piercing), and you are knocked prone. All creatures within 20 feet must make a Dexterity saving throw or take 2d4 piercing damage from flying shrapnel.
Cleaning
Spending 1 hour cleaning the Arcanum Cataclysm (including during a long rest) resets both the jamming and explosion risks to zero.
Overheat
When this happens, you take 1d4 fire damage, and the weapon cannot be fired again until you spend 1 action to cool it down. When the Belt Fed attachment is equipped, if you fire the weapon 6 times (Attacks per action) in a single turn without allowing it to cool, it is overheated until the end of your next turn.
Restrictions
- During a long rest, you must choose to either recharge spent Arcane Essence Crystals or clean the weapon—you cannot do both in the same long rest.
- The Crossbar attachment is incompatible with both the Scope slot and Belt Fed attachment. If you equip the Crossbar, you cannot equip a Scope or Belt Fed attachment.
- The Belt Fed attachment is incompatible with the Crossbar attachment and cannot be equipped simultaneously.
- While aiming, you can not move.(not to be confused with Aim)
Arcane Essence Crystals
Arcane Essence Crystals are powerful magical relics, each pulsing with primordial energy. When loaded into the Arcanum Cataclysm, they empower its attacks and abilities. Spent crystals can be recharged during a long rest by channeling arcane energy.
Additional arcane magazines can be found as treasure, purchased, or crafted by skilled artificers. While the weapon can be loaded with mundane bullets in a pinch, only Arcane Essence Crystals allow it to reach its full potential.
Extended Description
Renowned among adventurers for its adaptability, the Arcanum Cataclysm transforms to meet the needs of any battlefield. Its modular construction allows for a variety of attachments—each unlocked through deeds of heroism—making every weapon unique to its wielder. Tales abound of legendary exploits achieved with specialized configurations, whether providing covering fire for companions, breaking enemy lines with devastating barrages, or holding a fortress against impossible odds. Yet the Cataclysm is more than a mere weapon. Sentient and enigmatic, it judges those who would wield it—accepting only those whose ambitions, resolve, or spirit resonate with its arcane purpose. To seek out and test those with the ambition to reshape the world. Those found unworthy may find the weapon’s strength elusive, or even turned against them. In the right hands, the Cataclysm is a symbol of tactical ingenuity and the ever-evolving bond between warrior and artifact.
Tactical Enhancements
Attachment Slots: Each firearm has 1 slot for each of the following attachment types:
- Muzzle
- Barrel
- Underbarrel
- Magazine
- Rear Grip
- Stock
- Laser
- Fire Mod
A gun can only have one attachment of each type equipped at a time.
Available Attachments: There are 39 unique attachments. Attachments for each slot must be unlocked in order, starting with the first listed attachment for that slot. You cannot unlock or equip a higher-tier attachment until all previous attachments in that slot have been unlocked. The player may freely choose from the full list when customizing their firearm after unlocking attachments.
DM Tip: It’s up to the DM which option unlocks the attachments.
Changing Attachments:
- You may only change attachments during a long rest.
- During a long rest, you may swap any number of attachments, provided you have access to your equipment and tool (tinker’s tool).
- Attachment Storage: All attachments are automatically stored in a Bag of Holding integrated into the harness (excluding the increased holding capacity). Players never need to manage or track the weight or storage of unlocked attachments; any attachment you acquire is always available and securely stored.
DM Tip: Switching attachments takes an action or bonus action at your discretion.
Modular Add-Ons:
Muzzle Attachments
- Suppressor: Attacks do not reveal your position by sound; enemies have disadvantage on Perception checks to detect you by noise (Unlock after 5 successful attacks with the firearm or 100 GP).
- Mobility Spread Muzzle: No attack penalty while moving; advantage on attacks if you moved 10+ feet this turn (Unlock after 10 successful attacks or 150 GP.)
- Compensator: +1 bonus to attack rolls due to recoil control(Unlock after 15 successful attacks or 200 GP.)
- Firepower Suppressor: Stealthy attacks, +25% weapon range, ignore half cover, advantage on initiative, but -1 to attack rolls (Unlock after 20 successful attacks or 250 GP.)
- Muzzle Brake: Advantage on first attack each turn; +2 to attack rolls; recover from misfires or jams faster(Unlock after 25 successful attacks or 300 GP.)
Barrel Attachments
- Long Barrel: +10 feet to the weapon’s range; reload as a bonus action once per short rest (Unlock after 8 successful attacks or 125 GP.)
- Bullet Velocity Barrel: Ignore disadvantage on long-range attacks; ranged attacks ignore resistance to piercing damage. (Unlock after 14 successful attacks or 175 GP.)
- Damage Barrel: +1d4 bonus damage on critical hits; +2 to attack rolls against heavily armored targets; +2 to headshot damage (if using headshot rules) (Unlock after 5 crits or 225 GP.
- Short Barrel: Advantage on initiative and attacks in the first round; can attack as a bonus action after dashing or jumping, once per short rest. (Unlock after 20 successful attacks or 275 GP.)
- Hybrid Barrel: +10 feet to range; ignore up to three-quarters cover at long range. (Unlock after 32 successful attacks or 350 GP.)
Underbarrel Attachments
- Steady Sway Handstop: Ignore penalties for firing after moving or while aiming; +1 to attack rolls while not moving; resist forced movement (advantage on saves vs being pushed)(Unlock after 7 successful attacks or 110 GP.)
- Mobility Handstop: +5 feet to movement speed; ignore difficult terrain for 1 turn after firing; advantage on attacks after dashing. (Unlock after 13 successful attacks or 160 GP.)
- Stable Focus Handstop: Can “hold breath” as a bonus action: gain +2 to attack rolls and resistance to being frightened until the end of the turn; advantage on saves vs stun/disarm. (Unlock after 19 successful attacks or 210 GP.)
- Crossbar: +2 to attack rolls against targets in cover (Unlock after 25 successful attacks or 260 GP.)
- Recoil Control Foregrip: Ignore disadvantage from being moved or jostled when firing; +2 to attack rolls due to superior recoil control. (Unlock after 31 successful attacks or 310 GP.)
- Mobile Recoil Foregrip: +5 feet to movement speed; can move at full speed while firing; ignore disadvantage for firing after sprinting. (Unlock after 37 successful attacks or 370 GP.)
Magazine Attachments
- Fast Mag I: Reload as a bonus; +5 feet speed after reloading; +2 initiative 50% ammo capacity reduction (Unlock after 10 successful attacks or 140 GP).
- Extended Mag I: 50% more ammo capacity; +2 initiative (Unlock after defeating 3 enemy types or 180 GP).
- Extended Mag II: Double ammo capacity; +2 initiative (Unlock after victory in a major battle or 260 GP).
- Belt Fed: Three times ammo capacity; you can now make 6 extra attack actions. You can also move at full speed while aiming or firing. Risk of overheating, please see weapon stability. (Unlock after you travel to the heart of a dying star, survive a hurricane, and swim through a lake of lava during an adventure, or at your DM’s generosity, or pay your DM $50.00.)
Rear Grip Attachments
- Sprint to Fire Grip: After dashing, attack as a bonus action once per short rest; ignore disadvantage for firing after sprinting or jumping. (Unlock after 9 attacks made after dashing or jumping or 120 GP)
- Quickdraw Grip: Advantage on initiative rolls; may attack as a bonus action if you haven’t moved more than 10 feet this turn. (Unlock after 15 attacks made after drawing the weapon or 170 GP.)
- Stabilization Grip: +1 to attack rolls; ignore recoil penalties. (Unlock after 21 successful attacks or 220 GP.)
- Mobile Quickdraw Grip: May attack as a bonus action after sliding or diving prone; advantage on saves against being stunned or frightened. (Unlock after 27 attacks made after going prone or sliding or 270 GP.)
- Accuracy Grip: +2 to attack rolls with your first attack each combat; ignore disadvantage on attacks made immediately after standing up or moving. (Unlock after 33 successful attacks or 330 GP.)
Stock Attachments
- Mobility Stock: +5 feet movement speed; can move at full speed while firing; ignores difficult terrain on your turn after firing. (Unlock after 11 successful attacks or 130 GP.)
- Control Stock: +1 to attack rolls; ignore disadvantage from recoil; +5 feet movement speed while aiming; advantage on Dex saves to avoid being knocked prone. (Unlock after 17 successful attacks or 180 GP.)
- ADS Movement Stock: Move at full speed while aiming down sights; ignore opportunity attacks provoked by movement after firing. (Unlock after 23 attacks made while aiming down sights or 230 GP.)
- Tactical Spread Stock: Advantage on attacks from cover or while in a defensive stance; ignore penalties for hip-firing. (Unlock after 29 attacks made from cover or 280 GP.)
- Mobile Flinch Stock: Resistance to being stunned or frightened while aiming; +5 feet movement speed while aiming. (Unlock after 35 successful attacks or 340 GP.)
Laser Attachments
- MFS Motion Strike Laser: +1 to attack rolls while moving or firing from the hip; +10 feet to range; +5 feet movement speed after firing; visible laser may reveal your position. (Unlock after 12 attacks made while moving or 135 GP.)
- Strelok Laser: Ignore disadvantage when switching from hipfire to aimed attacks in the same turn; visible laser may reveal your position if enemies are watching. (Unlock after 18 attacks made where you hipfire and then aim in the same turn or 185 GP.)
- Tactical Laser: Advantage on attacks while in a defensive or tactical stance (e.g., behind cover). (Unlock after 36 attacks made from cover or in a tactical stance or 305 GP.)
- Steady Aim Laser: Advantage on attack rolls made from the hip or while sliding/jumping/diving; a visible laser may reveal your position when hipfiring. (Unlock after 30 attacks made from the hip or while sliding/jumping or 245 GP.)
- Handling Laser: After sprinting, may attack as a bonus action; advantage on attacks made immediately after sprinting; a visible laser may reveal your position when firing from the hip. (Unlock after 24 attacks made after sprinting or 265 GP.)
Fire Mod Attachments
- High-Velocity Ammo: Ignore disadvantage on long-range attacks; ranged attacks ignore resistance to piercing damage. (Unlock after 14 successful long-range attacks or 175 GP.)
- Recoil Springs: +1 to attack rolls due to improved recoil control; ignore disadvantage from recoil or rapid firing. (Unlock after 20 attacks with no missed shots in a row or 225 GP.)
- Rapid Fire: Gain one additional attack per Attack action once per short rest; +10 feet to weapon range; attacks made this way suffer -1 penalty to attack rolls. (Unlock after 26 attacks in a single combat encounter or 285 GP.)
- FMJ Ammo: Ranged attacks ignore half and three-quarters cover; deal double damage to objects and constructs; ignore piercing resistance. (Unlock after 32 attacks made against armored or covered targets or 345 GP.
It’s up to you to decide whether a character has proficiency with a firearm. Characters in most D&D worlds wouldn’t have such proficiency. During their downtime, characters can use the training rules in the Player’s Handbook to acquire proficiency, assuming that they have enough ammunition to keep the weapons working while mastering their use.
This weapon has the following mastery property. To use this property, you must have a feature that lets you use it.
Slow. If you hit a creature with this weapon and deal damage to it, you can reduce its Speed by 10 feet until the start of your next turn. If the creature is hit more than once by weapons that have this property, the Speed reduction doesn’t exceed 10 feet.
Notes: Bonus: Magic, Disadvantage: Stealth, Each time you use the Arcane Gun’s special ability without cleaning it, roll a d4 for jamming and a d6 for explosion—each roll gets riskier with every consecutive use. On a jam, the gun locks up until repaired and you lose your next action; on an explosion, the gun is destroyed and deals 4d10 Force and 4d10 Piercing to everyone within 10 feet, plus 6d4 piercing to everyone within 20 feet., creature. While attuned, the sentient light machine gun is more cooperative. However it will judge your soul., Damage, Buff, Combat, Sentient, Artificer, enchantment, Range, Two-Handed, Ammunition (Firearms), Burst Fire, Reload, Slow
Previous Versions
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