An Assassin's Creed / Hitman-Style Stealth Subsystem for D&D 5e
Fifth Edition has a problem with stealth missions.
You're a Level 10 Rogue. Assassin subclass, naturally. You've killed nobles in their beds, slipped past royal guards, disappeared entire merchant caravans without a trace. This is what you were built for.
Tonight's job is simple: infiltrate the compound, eliminate the sentries, free the prisoners. You've scouted the patrol routes. You know there's a guard on the eastern platform. Lone target, looking the wrong way. Easy pickings.
You roll Stealth. Natural 18, plus your +13 modifier. Thirty-one. You're a shadow. You're a whisper. You're already behind him before he knows you exist.
Blade comes out. You're an Assassin, so against a surprised target you get automatic critical hits. This is your moment. This is the entire reason your subclass exists.
Let's do the math.
The guard is a Veteran statblock. 58 hit points. Beefy for a grunt, but you're a specialist. You've got this.
You roll damage.
Let's just sit with that for a moment.
You snuck up on a man who had no idea you were there. You put a blade across his throat. In what world is that "a flesh wound"? In what universe does someone take a critical hit dagger across the jugular from a trained killer and think "I'll walk that off"?
But he has 19 hit points, so he screams.
Roll initiative.
Your "assassination" is now a fistfight on a wooden platform, and every guard in the compound just heard it happen. The ranger in your party sighs and nocks an arrow. The paladin starts rolling for Smite. The stealth mission is over, and you're about to spend the next forty-five minutes grinding through a combat encounter you were specifically designed to skip.
You did nothing wrong. Your Stealth was phenomenal. Your positioning was perfect. You got the surprise, you got the crit, you got every single advantage the system offers.
And the guard is fine. Bleeding, sure. Angry, definitely. But fine.
There is no such thing as assassination in 5e. Only combat with a head start.
The Assassin's Codex bridges the gap between two unsatisfying extremes:
The DM waves their hand and says "yeah, he's dead." No rolls, no tension, no risk. You ghost through the compound like a cutscene. It works, but it doesn't feel earned. Where's the drama?
Every takedown funnels into standard combat. Stealth becomes a polite fiction, something you do before the fight, not instead of the fight. Players stop bothering with infiltration because the mechanics actively punish it.
The Assassin's Codex sits in the middle.
When you get the drop on a target, the kill itself is the roll, not your damage dice. A single d20 against their Challenge Rating determines the outcome: clean kill, messy struggle, or complete disaster. Your character build determines what happens when things go sideways. And when the alarm finally sounds, it's because you failed at the moment of truth, not because probability betrayed you on 12 dice that were supposed to be your specialty.
This is assassination with teeth. Every guard is a genuine decision. Every approach is a calculated risk.
And when you roll that Natural 20 on a takedown? He's just dead. Silent. Instant. Earned.
The way it should have been all along.
No initiative has been rolled. You are operating in stealth, not active engagement.
Your entire movement must be spent reaching the target. You are committing to the kill.
The target must be unaware of your specific position. They can be alert to danger generally.
Target eliminated silently and instantly. No sound, no struggle, no complications. Body remains where it falls.
You have your hands on them but it is messy. Roll your Subdue Dice. If you meet or exceed their HP, messy kill. If not, proceed to Scramble Round.
Things have gone wrong but you have one chance to salvage before full alert. This is NOT initiative. Choose from Silence, Subdue, Abort, Redirect, or Creative.
Only applies to CR 2+. They caught your wrist. You do not even get a chance. Alert triggers immediately, target gets free attack or raises alarm.
| CR | Clean Kill | Subdue Phase | Scramble Round | Complete Fail |
|---|---|---|---|---|
| 0 | 2+ | — | 1 | — |
| ⅛ | 3+ | 2 | 1 | — |
| ¼ | 4+ | 2–3 | 1 | — |
| ½ | 5+ | 2–4 | 1 | — |
| 1 | 6+ | 2–5 | 1 | — |
| 2 | 8+ | 3–7 | 2 | 1 |
| 3 | 9+ | 4–8 | 2–3 | 1 |
| 4 | 11+ | 5–10 | 2–4 | 1 |
| 5 | 12+ | 6–11 | 2–5 | 1 |
| 6 | 14+ | 7–13 | 3–6 | 1–2 |
| 7 | 15+ | 8–14 | 4–7 | 1–3 |
| 8 | 17+ | 9–16 | 5–8 | 1–4 |
| 9 | 18+ | 11–17 | 6–10 | 1–5 |
| 10 | 20 only | 15–19 | 11–14 | 1–10 |
CR 10 is the maximum CR that can be targeted with a takedown attempt.
| Level | Base Dice | Example (+4) |
|---|---|---|
| 1 | 2d6 | 6d6 (avg 21) |
| 2 | 3d6 | 7d6 (avg 24) |
| 3 | 4d6 | 8d6 (avg 28) |
| 4 | 5d6 | 9d6 (avg 31) |
| 5 | 6d6 | 10d6 (avg 35) |
| 6 | 7d6 | 11d6 (avg 38) |
| 7 | 8d6 | 12d6 (avg 42) |
| 8 | 9d6 | 13d6 (avg 45) |
| 9 | 10d6 | 14d6 (avg 49) |
| 10 | 11d6 | 15d6 (avg 52) |
| Level | Base Dice | Example (+5) |
|---|---|---|
| 11 | 12d6 | 17d6 (avg 59) |
| 12 | 13d6 | 18d6 (avg 63) |
| 13 | 14d6 | 19d6 (avg 66) |
| 14 | 15d6 | 20d6 (avg 70) |
| 15 | 16d6 | 21d6 (avg 73) |
| 16 | 17d6 | 22d6 (avg 77) |
| 17 | 18d6 | 23d6 (avg 80) |
| 18 | 19d6 | 24d6 (avg 84) |
| 19 | 20d6 | 25d6 (avg 87) |
| 20 | 21d6 | 26d6 (avg 91) |
Attempt to kill them through brute force. If you drop them to 0 HP, no alert. If not, they scream.
Grapple and choke them out. Win = restrained and silenced, finish next round. Lose = they break free and alert.
Disengage and vanish. Success = they are alarmed but do not know where you are. Fail = spotted and alert.
Blame someone or something else. Success = "Must have been the wind" or blame another NPC. Fail = alert.
Pitch something creative to your DM. They will set an appropriate ability check based on what you describe. This is where the best stories happen.
Every class can attempt takedowns. The mechanics are identical, but the narrative should reflect class identity.
Takedowns cannot be attempted against the following:
Out of combat + All movement used + Target unaware
Flat d20, no modifiers. CR determines difficulty.
(Level + 1)d6 + (Ability Mod)d6 vs HP
Clean Kill → Subdue → Scramble → Complete Fail
CR 10 (adjusted by Alert State)
Target CR = risk. Your level = salvage capacity.
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