Arc
Arc — The Encounter
Forgebound juggernaut, lightning sealed in living steel · a boss your table can run with almost no prep. SRD 5.1-compatible.
Who Is Arc
The Horrors of Sodom did not raise Arc; they bound it. When the city's arcane reactors first roared to life, raw lightning was poured into a shell of consecrated iron until the metal learned to want. What walked out of the forge was no servant but a sentinel, a thing that remembers only the command to hold the line and the hunger of the charge that sustains it. Its blade is a length of that same captive storm, sharpened to a blue edge that does not cool. Smiths feed it bolts of lightning the way a beast is fed meat, for a hungry Arc grows brittle and a sated one cannot be stopped. It speaks nothing, yet those who have fought beside it swear the humming in its chest answers their fear. Wherever the enchanted streets of the mystic city need a wall of steel, the forge-priests loose Arc, and the storm walks.
Run Arc in Sixty Seconds
- Never feed it lightning. Overcharged Core turns any lightning damage into 15 temp HP plus bonus storm damage on its next swing. Switch lightning casters to other elements the moment they see the blue glow.
- Open by clustering control. Lead with Thunderclap Slam (DC 15, 10-ft. burst) when two or more PCs bunch up, then follow with Multiattack on whoever fell prone.
- Kill-priority: break the front line first. Arc wants to pin melee fighters in place; drop or displace it before it isolates your backline, or pull the backline out of its 30-ft. reach.
- When bloodied, it commits. Below half HP it stops repositioning and full-attacks the nearest target every round, using Surge Step to catch anyone who runs.
- Three ways to run it: a lone juggernaut blocking a doorway; a paired bodyguard beside a forge-priest caster; or one of several identical wardens forming a moving wall.
Arc
Medium construct, lawful neutral
CR 6 · 2,300 XP · GUIDELINEOvercharged Core. Signature. Arc's frame hums with bound lightning. The first time each round Arc takes lightning damage, it gains 15 temporary hit points and its next melee attack before the end of its next turn deals an extra 9 (2d8) lightning damage.
Forgebound Resilience. Arc has advantage on saving throws against being knocked prone, and ignores difficult terrain caused by rubble, debris, or the lair it was forged to defend.
Actions
Multiattack. Arc makes two attacks with its Arc-Blade.
Arc-Blade. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 13 (2d8+4) slashing damage plus 4 (1d8) lightning damage.
Thunderclap Slam (Recharge 5-6). Arc drives its blade into the ground. Each creature within 10 ft. must make a DC 15 Dexterity saving throw, taking 22 (4d10) thunder damage and being knocked prone on a failure, or half damage and not knocked prone on a success.
Bonus Actions & Reactions
Surge Step. Reaction (recharges after Arc takes lightning damage): When a creature within 5 ft. moves away, Arc moves up to 15 ft. in a straight line toward it without provoking opportunity attacks.
A towering warrior sealed in dark forge-plate, its joints and the long edge of its greatsword bleed crackling blue light, with veins of molten orange running through living steel.
Arc, Bound
Companion · acts on your initiative
Bound · GUIDELINEStorm Ward (signature). While Arc is within 5 ft. of you, you have resistance to lightning damage, and the first time each turn a creature hits you with a melee attack, that creature takes 5 (1d10) lightning damage.
Actions
Arc-Blade. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 11 (2d8+3) slashing damage plus 4 (1d8) lightning damage.
Reactions
Interpose. When an ally within 5 ft. is hit by an attack, Arc may take half the damage in their place and shove the attacker 5 ft. back.
Bound to a worthy hand, Arc stands as a living rampart, its core flaring brighter each time a blow lands near those it has chosen to guard.
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 closing on the squishiest caster and forcing them to flee or fight in melee. If the party clusters, use Thunderclap Slam to scatter and knock prone. Pair it with weaker forge-thralls so it can hold the front while they swarm flankers.
Open by marking the heaviest melee threat and grinding it down with two Arc-Blade hits. Bait the party into using lightning so Overcharged Core fuels its temp HP and bonus damage. When clustered foes appear, lead with Thunderclap Slam; use Surge Step to chase any caster who tries to back away.
Run Arc as the anchor of a forge-warden line, not a solo: station it in a chokepoint with ranged thralls behind. Kill-priority is whoever throws lightning, since they accidentally recharge it. Pair it with a bigger threat so the party can't ignore the wall while it pins their front rank prone.
Put Arc 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 Arc?
Arc's home stat block is Challenge Rating 6 (2,300 XP), tuned for a party of levels 5-10. Scaled versions are provided for tiers 1 (levels 1-4) and 3 (levels 11-15) using the same traits and tactics, only the numbers move.
Can Arc be a companion or ally?
Yes. The companion block 'Arc, Bound' lets a worthy character bind the construct as a living rampart: it grants nearby lightning resistance and a retaliatory shock via Storm Ward, swings its Arc-Blade, and can Interpose to soak a hit meant for an ally. Use it at about 60 percent of the adversary's hit points to keep it from overshadowing the party.
Why does my lightning sorcerer make Arc tougher?
By design. Overcharged Core feeds on lightning, granting Arc temporary hit points and extra damage whenever it is shocked. Against this construct, lean on fire, force, radiant, acid, or plain weapon damage and save lightning for other foes.
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
Played Arc at your table? Log in with your Obsidian Tavern account to leave a balance note, a war story, or a file issue — the sharpest reports get the block revised.
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