Serpentarius
Serpentarius — The Encounter
The Horned Slaughter-Spirit, Twin-Axed Bull of the Pit · a boss your table can run with almost no prep. SRD 5.1-compatible.
Who Is Serpentarius
In the older grimoires Serpentarius is named among the goading spirits, a horned executioner set loose where blood has already been spilled. He is not summoned to bargain but to finish, drawn to the wounded as a hound to a struck deer, and the scholars warn that his appetite quickens with every cut already opened in a foe. He carries two axes because, the texts say, he refuses to ever lower a guard; the second blade answers any hand raised against him before that hand can fall. Soldiers who survived his passing describe a smell of hot iron and the way he lowers his head to charge, horns first, scattering a shield-wall like chaff. He keeps to the lawful pacts of his kind, taking only what is owed and no more, yet what is owed to him is measured in slaughter. Bind him at your peril, for a contract that names blood as its price is a contract he will always overfulfill, and he counts the surplus as his fee.
Run Serpentarius in Sixty Seconds
- Charge first. Always move 20+ feet in a straight line before the first axe swing — the horns add piercing damage and a DC 15 prone, setting up the whole turn.
- Hunt the wounded. Blood Frenzy gives advantage against anyone missing hit points, so steer every Multiattack into the most damaged PC rather than the tankiest.
- When bloodied, escalate. At half HP its axes add 1d8 — stop retreating, plant in melee, and trade blows; it is now winning the damage race.
- Three ways to run it: as a charging shock-trooper that knocks lines down, as a wound-finisher that cleans up softened targets, or as a reactive wall that punishes every attacker with Vengeful Hew.
- Recharge discipline. Hold Horn Sweep until two or more characters cluster (revive, heal, gang-up) — the 4d8 arc plus pushback breaks up their formation.
Serpentarius
Large fiend (devil), lawful evil
CR 6 · 2,300 XP · GUIDELINEGoring Charge. If Serpentarius moves at least 20 feet straight toward a creature and then hits it with an axe attack on the same turn, the target takes an extra 7 (2d6) piercing damage from its horns and must succeed on a DC 15 Strength saving throw or be knocked prone.
Blood Frenzy. Signature. Serpentarius has advantage on melee attack rolls against any creature that does not have all its hit points. While at half its hit points or fewer, its axe attacks deal an extra 4 (1d8) slashing damage.
Magic Weapons. Serpentarius's weapon attacks are magical.
Actions
Multiattack. Serpentarius makes two Twin Axe attacks.
Twin Axe. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 14 (2d8 + 5) slashing damage.
Horn Sweep (Recharge 5-6). Serpentarius sweeps its horns and axes in a wide arc. Each creature within 5 feet of it must make a DC 15 Dexterity saving throw, taking 22 (4d8 + 4) slashing damage on a failed save, or half as much on a success. Creatures that fail are pushed 5 feet away.
Bonus Actions & Reactions
Vengeful Hew. When a creature Serpentarius can see hits it with an attack, it can use its reaction to make one Twin Axe attack against that creature.
A towering, bull-horned brute clad in spike-riveted infernal plate, Serpentarius wades into the press dragging twin cleaving axes whose heads are notched with old kills. Its red, sinew-corded flesh steams where iron meets it.
Serpentarius, Bound
Companion · acts on your initiative
Bound · GUIDELINEPress the Wound (signature). The bound spirit has advantage on melee attacks against any creature missing hit points, hammering whatever the party has already softened up.
Actions
Twin Axe. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 13 (2d8 + 4) slashing damage. Serpentarius can attack twice on its turn.
Reactions
Guard Never Lowers. When an ally within 5 feet is hit by a melee attack, Serpentarius can make one Twin Axe attack against the attacker.
Chained to a hard-handed oath-breaker, the horned slaughter-spirit fights as a tireless front-line wall, but it loathes mercy and will mock any companion who spares a fleeing enemy.
Guideline numbers — formula-tuned and read from the miniature's design, not yet table-proven. Tell us how it ran in the comments.
How It Fights — by Tier
Same creature, scaled threat. The traits never change; only the numbers move.
Open by charging the softest-looking target to knock it prone, then chop with both axes. Save Horn Sweep for when two or more characters bunch up to heal or revive. Pair it with a single caster or controller so the party cannot simply kite it.
Charge the most wounded PC first — Blood Frenzy gives advantage and it hits harder once anyone is bloodied. Recharge Horn Sweep into clustered melee, and let Vengeful Hew punish whoever swings at it. Kill-priority is the healer; deploy it as the bruiser anchoring a warlord's line, not alone.
Run it with minions or in a lair where it can charge across open ground each round. Open on the most damaged front-liner, sweep clustered targets, and react into any melee striker. It is a finisher, not a centerpiece — pair it with a bigger horned commander so the party faces two real threats at once.
Put Serpentarius on the table
Download the presupported STL and run the fight tonight — the model, and the encounter that comes with it.
Get the STL on MyMiniFactory →Clay Cyanide Companion Rules v1
How a bound creature acts
- A companion acts on its owner's initiative, immediately after the owner.
- It uses the Companion block above — roughly ×0.6 HP and damage, no recharge abilities, and at most one reaction trait.
- It moves freely; it takes its Action only while its owner is conscious.
- At 0 HP a companion is broken, not dead — restored on a long rest unless your table rules otherwise.
Original Clay Cyanide material © Clay Cyanide LLC — explicitly not the non-SRD official sidekick rules.
Questions, Asked at the Table
What CR is Serpentarius?
Natively CR 6 (2,300 XP) — a Tier 2 bruiser for a party of levels 5-10. Use the Tier 1 line (~CR 2) for levels 1-4 or the Tier 3 line (~CR 11) for levels 11-15; traits stay identical, only AC, HP, to-hit, DC, and damage shift between bands.
Can Serpentarius be a companion or ally?
Yes — the bound profile (AC 16, 76 HP) makes a punishing front-line wall that presses wounded enemies and punishes anyone hitting its allies, but it is a lawful-evil slaughter-spirit and will resent any party that shows mercy.
Is Serpentarius a solo boss?
No. It has a real reactive kit but no legendary actions, so a four-PC party will out-act it on its own. Run it as the heavy in a warband, beside a caster or a larger commander, rather than as a lone centerpiece.
Tell Us How It Ran
This work includes material taken from the System Reference Document 5.1 ("SRD 5.1") by Wizards of the Coast LLC and available at dnd.wizards.com/resources/systems-reference-document. The SRD 5.1 is licensed under the Creative Commons Attribution 4.0 International License available at creativecommons.org/licenses/by/4.0/legalcode.
Clay Cyanide Miniatures is not affiliated with, endorsed, sponsored, or specifically approved by Wizards of the Coast LLC. This content is compatible with the fifth edition of the world's most popular fantasy roleplaying game. Companion rules, lore, names, and original mechanics © Clay Cyanide LLC.
Technical Specifications
32mm, 75mm
STL, Pre-supported STL
Standard or ABS-like resin, 0.05mm layer height
Yes — ready to print, optimized supports included
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