Marathon Runner Shells: Every Shell, Rook and Build Basics

Your Runner shell decides how every fight starts. One shell walls off a hallway, another goes invisible, another flies over the fight on a grapple. Picking the wrong one for how you play makes every run harder than it needs to be.

This guide covers all seven shells, Rook's solo mode, the changes that landed with the Nightfall Refresh, and how cores and implants shape a build.

What is a Runner shell?

A shell is the biosynthetic shell you wear on a run. Die, and your mind gets uploaded into a fresh one. Each shell is built around one job, like intel, healing or breaking a fight open.

You pick the shell, then push it in a direction with the cores, implants, weapons and mods you bring.

Every Marathon Runner shell

Here's what each shell is for, in one line.

• Destroyer (Front-line tank): Riot Barricade, missiles, Thruster
• Assassin (Stealth): Smoke Screen, Active Camo
• Recon (Intel): Echo Pulse, tracker drones, footstep trails
• Vandal (Mobility and disruption): Double jump, extended slide, knockback cannon
• Thief (Loot): Enhanced visor, Pickpocket Drone, Grapple
• Triage (Medic): Reboot+, Med-Drone

The seventh shell, Sentinel, came in Season 2 and plays a bit differently, so it gets its own section below.

Destroyer

The team's tank. It draws fire behind a Riot Barricade, fires missiles and uses thrusters to close the gap. Pick it if you like being the first one through the door.

Assassin

Smoke and camouflage let Assassin set up unseen strikes or slip out of a bad fight. Great if you'd rather pick the moment than trade shots in the open.

Recon

Recon finds people. Echo Pulse, tracker drones and holographic footstep trails tell your crew where the enemy is before they know you're there.

Vandal

Speed is the whole point. Vandal chains double jumps and long slides, then uses its knockback cannon to break an enemy line and get out again.

Thief

The loot goblin. Thief spots gear through walls, knocks loot off enemies with its piloted drone and swings away on a grapple when things go wrong.

Triage

The combat medic. Triage revives crewmates with Reboot+ and keeps them in the fight with a Med-Drone that also shares your consumable boosts.

Sentinel: the defensive shell

Sentinel controls space. It's at its best when the enemy has to come to you.

• Defender System: a platform that shoots down incoming explosives and boosts reload speed and stability for anyone standing near it.
• Snare Mine: a proximity mine that bursts into immobilizing submunitions.
• Prey Tracker: shows moving enemies on radar in a cone in front of you.
• Castle Doctrine: faster SMG, pistol and shotgun handling the more hostiles are nearby, plus a short defensive boost after splash damage.

Rook: the solo scavenger

Rook isn't a normal shell pick. It's a scavenger mode: you drop alone into a match that's already running, with no loadout and nothing at risk.

Its tactical ability keeps you hidden from UESC, so you can sweep for loot and get out. Flares were removed in the Nightfall Refresh, but Rook still starts with a Compromised Sneak Pack, two Claymores, a Depleted Self Revive and a Signal Jammer.

Cores and implants: building your shell

Two kinds of gear change how a shell plays, and they work differently.

• Cores are generally designed for one shell and change how its abilities work. One Thief core, for example, gives you a second Grapple charge.
• Implants fit any shell. Each one gives a stat package plus perks. Higher-tier implants carry two perks: one fixed and one random.

Your Cradle sits on top of all this and raises your baseline stats. Our Cradle guide explains how to spend that Energy.

What changed for shells in the Nightfall Refresh

A few shell changes landed on October 6, and Recon took the biggest one.

• Echo Pulse: now fires in a cone where you aim, not all around you. It also staggers non-Runner combatants the first time it hits them.
• Interrogation: the warning a pinged Recon gets now comes two seconds later.
• Riot Barricade: no more switching it off by accident before it goes up.
• Invisibility: it now flickers after 0.2 s (was 0.9 s) if you fire while invisible.

The full list of resets is in our Nightfall Refresh guide.

How to pick your shell

1. Play for your crew. A trio with Recon for intel and Triage for revives covers a lot of mistakes.
2. Solo? Think about escapes. Assassin, Vandal and Thief all have a built-in way out of a bad fight.
3. Like holding ground? Destroyer and Sentinel reward you for making the enemy come to you.
4. Try every shell once. Exfil with all seven and you complete the Renaissance Runner Codex challenge.
5. Pick cores before implants. Cores change what your shell does, implants add stats and perks.

Want a shell mastered without the grind? CarrySquad's Marathon Runner Mastery service can handle it.

FAQ

More Marathon guides: Factions, Cradle, Nightfall Refresh, Cryo Archive and Vault Breaker.