SER KARTHOS
SER KARTHOS — The Encounter
Knight-Apostle of the Yellow Sign, enforcer of the tattered cult · a boss your table can run with almost no prep. SRD 5.1-compatible.
Who Is SER KARTHOS
They name him Ser Karthos, though the man beneath the mask is long unmade. Once a sworn knight, he knelt before the Tattered Sign and rose an apostle, his oath transmuted from king to a thing that wears a pallid mask. The Sereth are not mere followers; the Yellow Sign shapes their very purpose, and Karthos stands first among them, granted authority over the cult's inner ranks. Part knight, part preacher, he drives lesser cultists and corrupted brutes forward through presence and dread alone, his murmured liturgy curdling the resolve of any who hear it. Where he plants his halberd, the faithful do not break. His armor is ritual-scarred plate, every spike a vow; his tabard, the dyed shroud of a fallen city. To meet his masked gaze is to glimpse the geometry behind it, and to forget, for a moment, why you came to oppose him at all.
Run SER KARTHOS in Sixty Seconds
- He's a leader, not a duelist. Always run Ser Karthos with minions inside his 20-foot Aura of Dread Command. Without bodies near him, half his kit does nothing.
- Open with the Mark. First turn, brand the party's biggest threat (DC 14 Wis or frightened). A frightened damage-dealer with disadvantage swings your whole opening.
- Kill-priority is the back line. His Sigil-Blade adds 2d6 psychic, so he wants squishy casters; if his aura is feeding a brute's hits, the brute goes for the front.
- When bloodied (60 HP), turtle behind the brutes. Use Enforcer's Rebuke every round and let Living Shield brutes eat the hits while he keeps the aura up.
- Three ways to run him: cult enforcer leading 4 cultists (T1), armored anchor for a brute pack (T2 native), or a lieutenant guarding a chokepoint beside a flagship horror (T3).
SER KARTHOS
Medium humanoid (cultist), lawful evil
CR 6 · 2,300 XP · GUIDELINEAura of Dread Command. Each allied cultist or brute within 20 feet of Ser Karthos has advantage on saving throws against being frightened, and deals an extra 3 (1d6) damage on its first weapon hit each turn while he is conscious. This is the signature trait that makes him a battlefield leader rather than a lone fighter.
Mark of the Tattered Sign. When Ser Karthos reduces a creature to 0 hit points, or as a bonus action he can brand a creature he can see within 30 feet. The marked creature must succeed on a DC 14 Wisdom save or be frightened of him until the end of its next turn.
Actions
Multiattack. Ser Karthos makes two attacks: one with his halberd and one with his sigil-blade.
Halberd. Melee Weapon Attack: +7 to hit, reach 10 ft., one target. Hit: 14 (2d10+4) slashing damage.
Sigil-Blade. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 9 (1d8+4) slashing damage plus 7 (2d6) psychic damage as the Yellow Sign bites at the mind.
Bonus Actions & Reactions
Enforcer's Rebuke (Reaction). When a creature Ser Karthos can see hits an ally within 10 feet of him, he makes one halberd attack against that creature.
A spike-pauldroned champion shrouded in a tattered yellow tabard, his hooded face hidden behind a leering mask, a halberd slung over one shoulder and a sigil-marked blade at his hip.
SER KARTHOS, Bound
Companion · acts on your initiative
Bound · GUIDELINEMindless Devotion (signature). The SER KARTHOS has advantage on saving throws against being charmed or frightened, and cannot be turned. While within 20 feet of an allied champion, it ignores the first 5 damage of each hit it takes.
Actions
Crushing Slam. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 13 (2d8+4) bludgeoning damage, and a Large or smaller target must succeed on a DC 13 Strength save or be knocked prone.
Reactions
Living Shield. When an allied champion within 5 feet is hit by an attack, the SER KARTHOS takes the damage instead.
A heavily corrupted thrall built for raw force, deployed to overwhelm defenses and crush resistance at its master's word.
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 branding the toughest-looking PC with Mark of the Tattered Sign, then close to halberd reach so his Enforcer's Rebuke punishes anyone who swings at his cultists. Kill-priority is healers; he will chase them past his own line. Run him with 2-4 weak cultists so his Aura of Dread Command actually means something.
Open by positioning so the most allies sit inside his 20-foot aura, then Multiattack the frontline PC and use Mark on whoever tries to flank. Hold his reaction for the first ally who gets hit. He is an add-on, not a duel: pair him with a bigger eldritch threat or a pack of brutes and let the aura amplify their hits while he tanks the front.
Field him in a lair or cult vanguard with several brutes so the Aura of Dread Command turns a mob into a wall. Open on the squishiest caster with both attacks and a Mark, then guard the line with Enforcer's Rebuke. He is a lieutenant: pair him with a flagship eldritch horror and let Karthos buy it time by holding the chokepoint.
Put SER KARTHOS 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 SER KARTHOS?
His home build is CR 6 (2,300 XP), tuned for a level 5-10 party. Stat blocks are also provided at CR ~2 (levels 1-4) and CR ~11 (levels 11-15); the traits stay identical and only the numbers shift.
Can SER KARTHOS be a companion or ally?
He is built as an adversary, but nothing stops a renegade-knight redemption arc. As written he is a leader who buffs nearby allies, so he makes a far better commander of a friendly war-band than a lone bodyguard.
Is Ser Karthos a solo boss?
No. He has no legendary actions and his whole kit (aura, rebuke reaction, Mark) assumes allies on the field. Run him as the armored anchor of a cult cell, or as a lieutenant beside a bigger eldritch threat, not as a one-versus-party finale.
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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