From triage to triumph: the definitive Obi guide to keeping squads alive on Hell on Earth
If your team is a body, Obi (Medic) is the heartbeat. In Killing Floor 3, he’s not just a walking first‑aid kit—he’s a mobile clinic that slows, weakens, and breaks ZED momentum while topping everyone off. The big changes this time: a dedicated healing gadget (Sanctum), grenades that heal and debuff, and weapon choices/mods that turn every pull of the trigger into battlefield control. Played well, Obi makes hard waves feel fair and boss phases winnable. Played poorly, you’ll burn syringes and watch the wipe timer tick. Let’s make you the former.
Obi 101: What actually heals (and why it matters)
Weapons. Medic’s armory includes:
- LF‑85 (special rifle): the backbone of high‑level healing; damaging enemies rapidly refills your healing darts, letting you sustain allies nearly nonstop. Pair it with the right ammo mod and it becomes an “infinite” team top‑off engine.
- K&W MP6 / VS‑11 (SMGs): steady trash clear and tag enemies to fuel heals; the MP6 can mount a Healing Grenade Launcher underbarrel for on‑demand AoE sustain.
- KH‑380 (sidearm): burst‑fast healing darts—with mods like Instant Heal Darts and Dart Recharger Kit, this pistol becomes your “panic defib.”
You can also buy cross‑perk weapons later (e.g., to shore up DPS) once your medical core is online. Roles are flexible; weapons aren’t hard‑locked to one Specialist outside of the starting kit.
Gadget — Sanctum. Drop a Sanctum to create a safe zone: healing allies, slowing/damaging enemies inside, and (with Resuscitator) even reviving downed teammates when you trigger the expansion blast. Skill picks like Field Hospital, Storm Shelter, or Energy Cycle can supercharge sustain, uptime, and team gadget recharge.
Throwables — Biotic Grenade. Your green cloud isn’t just a heal. With Anesthetist it applies Enfeeble (slowing attacks/movement), Gas Expansion increases radius, Lingering Cloud extends duration, Urgent Care pauses bleed‑out and revives inside the cloud, and Waste Collector spits out pickups that refund a Syringe. Used right, your nades are mini‑ults on short cooldowns.
Passives that change fights.
- Social Distancing: revive at range by shooting healing darts into a downed ally—no risky hand‑revives.
- Symbiosis: when you heal others, you get healed—keeps you alive while you’re clutch‑healing.
- Stronger Prescription / Pill Mill / Doctor’s Bag / Chemical Reaction: enhance heal potency, max ammo, syringe utility, or spawn healing gas clouds on kills.
Pick to match your build (pure healer vs. hybrid).
About Syringes. Everyone gets limited Syringes (up to three by default, purchasable at the Trader between waves), and your Syringe Bag tool lets you drop extra charges for teammates. As Medic, passives like Doctor’s Bag buff the value of those bags (each bag gives two Syringes; using a Syringe repairs a bit of armor).
The Builds (tested philosophies you can adapt)
Below are four complete loadouts—two healer‑first, one hybrid DPS‑healer, and one early‑game economy route. Use them as templates; swap a skill or mod to match your team’s comfort and the map’s tempo.
1) Sanctum Commander (Pure Team Healer)
Goal: maximum uptime on heals, revives without risk, huge “green space” control.
Weapons
- Primary: LF‑85
Mods: Biomorphic Boosted Battery (massively increases heal output; adds heal‑over‑time at the cost of efficiency), Enhanced Foregrip/Reflex Sight (accuracy/handling), Overclocked or Undervolted Receiver (fire rate/damage tuning). Consider Cold Fusion Converter on barrel when you want Freeze pressure (CC vs. Scrakes/FPs during pushes). - Secondary: KH‑380
Mods: Instant Heal Darts, Dart Recharger Kit, Rapid‑Release Darts (burst + sustain package for emergency tops). - Tertiary (optional): K&W MP6 for trash control; slot Healing Grenade Launcher underbarrel if you’re often split from the team.
Tool
- Multi‑Tool for consistent utility (unlock armor lockers, enable ziplines, activate traps) unless your lobby lacks heals—then bring Syringe Bag. Multi‑Tool keeps tempo high and armor topped through lockers; Syringe Bag adds safety in pug lobbies.
Passives (priority order)
- Social Distancing (ranged revive)
- Symbiosis (self‑sustain while healing)
- Stronger Prescription (healing potency) or Pill Mill (ammo if you’re SMG‑heavy)
- Chemical Reaction (heal cloud on kills for ambient sustain)
Throwables
- Anesthetist (Enfeeble slow), Gas Expansion (bigger cloud), Lingering Cloud (longer zone), Urgent Care (revive in cloud). This gives you map control and hands‑free revives during chaos.
Gadget (Sanctum) picks
- Field Hospital (healing +55%), Storm Shelter (longer duration), Health Benefits (heal when it expires), Resuscitator (blast revives when activated). Swap Steroid Injection in when your team needs a damage steroid for boss burn.
How it plays
Anchor fights by pre‑placing Sanctum at natural chokepoints; call it out so teammates fight inside. Rotate grenades to pre‑soak pushes; hold KH‑380 darts for sudden burst (especially on the teammate kiting a Fleshpound). “Spray to heal”: tag ZEDs with LF‑85 to constantly recharge darts and keep Symbiosis rolling. If someone downs in the open, shoot‑revive with Social Distancing; if they’re surrounded, Urgent Care in first, Resuscitator blast to stand them up. This build hard‑carries pugs.
2) Street Cleaner (Hybrid Trash‑Clear Healer)
Goal: Clear clots/gorefasts fast while feeding constant heals—great on open maps and with DPS‑light teams.
Weapons
- Primary: K&W MP6
Mods: Healing Grenade Launcher (underbarrel), Reflex Sight, Lightweight Mag, Fast Action Receiver. For ammo, Hollow Point Rounds is a reliable damage bump that still plays nicely with team buffs and handling. - Secondary: KH‑380 (Instant Heal + Dart Recharger Kit) for urgent burst.
- Flex: Later waves, add LF‑85 if you need endless darts (drop some MP6 mods to fund it).
Tool
- Multi‑Tool to keep the team looting armor lockers and opening routes; swap to Syringe Bag for boss waves if your group burns through stims.
Passives
- Symbiosis, Stronger Prescription, Pill Mill, Chemical Reaction (you’ll be constantly killing trash, so you’ll proc plenty of healing clouds). Keep Social Distancing if your team often wipes on revives.
Throwables
- Gas Expansion + Lingering Cloud for large, persistent safety carpets. Add Anesthetist for slows; consider Waste Collector if your team needs Syringe regen mid‑fight.
Gadget
- Burn Unit (melt small ZEDs in Sanctum), Outreach Center (bigger field), then Field Hospital/Storm Shelter depending on difficulty. Finish on Resuscitator.
How it plays
You’re the front‑third of the formation: sweep weak ZEDs with MP6, drop healing nades where the brawl is thickest, and refresh Sanctum on the team’s retreat route. Hybrid works wonders when nobody else is on add duty, and you’ll still have darts for burst saves.
3) Budget EMT (Wave 1–3 economy route)
Goal: Survive early rounds, fund the LF‑85 quickly, and keep the team healthy without overspending.
Weapons & purchases by wave
- Start: VS‑11 + starter kit. Save for KH‑380 ASAP (it’s your early “life insurance”).
- First upgrades: Instant Heal Darts and Dart Recharger Kit on the KH‑380 if you can afford them; otherwise buy Syringes at the Trader and play conservative.
- Goal by midgame: LF‑85 with a sight and foregrip; then craft Biomorphic Boosted Battery when mats allow.
Tool
- Syringe Bag (pugs) or Multi‑Tool (coordinated groups who share armor lockers and trap routes).
Passives
- Early grab Stronger Prescription/Symbiosis for immediate impact; slot Social Distancing at 20 for safe revives as difficulty ramps.
Throwables/Gadget
- Gas Expansion first (cheap AoE value), then Health Benefits so your Sanctum “pays out” a team heal when it expires.
How it plays
Think like a triage nurse: don’t chase overextensions, call your Sanctum drops, and ration Syringes. Your job is to get to LF‑85 with solid attachments; once online, your sustain spikes and the lobby stabilizes.
4) Boss Paramedic (Freeze & Revive focus)
Goal: Turn boss phases into controlled burns—freeze key targets, keep buffs rolling, and mass‑revive if the room tilts.
Weapons
- LF‑85 with Cold Fusion Converter (adds Freeze; great control vs. heavy threats), plus Foregrip/Sight and a Receiver for stability. KH‑380 with Instant Heal Darts stays your “oh‑no” button.
Passives
- Social Distancing, Symbiosis, Stronger Prescription, Damage Plan (buff allies’ weapon damage after you heal them). Keep Chemical Reaction if your group needs ambient healing during add phases.
Throwables
- Anesthetist for Enfeeble (slow boss swing speed), Lingering Cloud for longer uptime under boss pressure, and Urgent Care as your “mass revive in place” tool.
Gadget
- Steroid Injection (ally damage buff inside Sanctum) + Field Hospital/Storm Shelter; finish on Resuscitator for emergency stand‑ups during burn windows.
How it plays
Park Sanctum where your DPS plans to hold; rotate grenades to keep Enfeeble up on the boss and create a revivable zone. Freeze with LF‑85 barrel procs to cut momentum, keep Damage Plan rolling by tagging allies after each dart burst, and Resuscitator if two or more go down.
Micro‑tech that separates great Medics from “green cloud enjoyers”
- Shoot to revive. If an ally drops in a death funnel, don’t run in. Social Distancing lets you revive safely from range with your weapon’s healing effects. Layer Urgent Care first if you can—it pauses bleed‑out and buys time.
- Sanctum discipline. Place it before the push, not after. Use Outreach Center for bigger radius on tight maps and Storm Shelter when waves last longer than your default field. Resuscitator is your get‑out‑of‑jail card—announce the blast so allies regroup inside.
- Grenades are tempo. Chain Anesthetist clouds on chokepoints and Gas Expansion/Lingering Cloud to hold space for rotations; treat your nade like a mini‑ult to swing fights.
- Mod with intent. Biomorphic Boosted Battery supercharges team sustain (heal‑over‑time stacks beautifully with Symbiosis and buff passives), while Cold Fusion Converter trades some raw DPS for control via Freeze—hugely valuable at high difficulties.
- Economy basics. Buy Syringes at the Trader between waves; if your team runs light on stims, consider Waste Collector or drop a Syringe Bag so nobody walks into a boss with zero charges.
- Cross‑perk with restraint. You can pick up non‑Medic weapons later, but don’t starve your LF‑85 / KH‑380 mods or Sanctum picks to chase damage. Your real DPS is preventing wipes—revives, slows, and permanent uptime.
Quick reference (copy/paste loadout cards)
Sanctum Commander (Pure Healer)
- LF‑85 → Biomorphic Boosted Battery, Reflex/Foregrip, Overclocked/Undervolted Receiver; KH‑380 → Instant Heal Darts + Dart Recharger; optional K&W MP6.
- Passives: Social Distancing → Symbiosis → Stronger Prescription (or Pill Mill) → Chemical Reaction.
- Throwables: Anesthetist, Gas Expansion, Lingering Cloud, Urgent Care.
- Gadget: Field Hospital, Storm Shelter, Health Benefits, Resuscitator.
- Tool: Multi‑Tool (coordinated) / Syringe Bag (pugs).
Street Cleaner (Hybrid)
- K&W MP6 (Healing GL, Reflex, Lightweight Mag, Fast Action Receiver, Hollow Points), KH‑380 panic darts; later add LF‑85.
- Throwables: Gas Expansion + Lingering Cloud (+ Anesthetist); Gadget: Burn Unit → Outreach Center → Field Hospital → Resuscitator.
Budget EMT (Early)
- Start VS‑11, rush KH‑380 (Instant + Recharger), then LF‑85 core; Gas Expansion first, Health Benefits on Sanctum; Stronger Prescription + Symbiosis.
Boss Paramedic
- LF‑85 w/Cold Fusion Converter; KH‑380 instant darts; Anesthetist/Lingering/ Urgent Care; Steroid Injection/Field Hospital/Storm Shelter/Resuscitator; Damage Plan passive if your team can capitalize.
Why these builds work (the short version)
- LF‑85 supremacy. The rifle’s healing ammo feedback loop is unmatched—damage fuels darts, darts fuel uptime. If you can maintain LOS and keep tagging ZEDs, your team’s HP bars rarely move.
- Sanctum as win condition. Correctly placed fields heal, slow, and revive—they’re the difference between scraping by and stabilizing hard waves. Resuscitator turns wipes into resets.
- Grenades define space. Enfeeble + longer/bigger clouds cut boss DPS and lock lanes, buying your carries time to delete priorities. Waste Collector turns skillful throws into resource refunds.
- Sidearm saves runs. A well‑modded KH‑380 delivers instant triage when Sanctum is on cooldown or an ally is isolated.
Common mistakes to avoid
- “I’ll revive you, cover me!” No. Shoot‑revive with Social Distancing or Urgent Care in the cloud. Hand revives are last resort.
- Dropping Sanctum on yourself only. Place it where the team will fight, not where you panic. Call it out and kite through it.
- Over‑modding DPS before sustain. Prioritize Biomorphic Boosted Battery (LF‑85), burst darts on KH‑380, and core gadget/throwable picks before you chase damage receivers.
- Ignoring Syringe economy. Buy between waves; if your lobby bleeds stims, slot Waste Collector or Doctor’s Bag to stretch supplies.
Alternate ways to spec (if you want to experiment)
- Double Dose (place two Sanctums; ally effects don’t stack): great on sprawling maps for leapfrogged safe zones.
- Steroid Injection + Damage Plan: lean into damage buffs when your team already dodges well.
- Hollow Point Rounds on MP6 + Chemical Reaction: rapid trash clear that leaves healing clouds behind.
Closing thoughts
Obi excels when you think like a map designer—you decide where fights are safe (Sanctum), when pushes slow (Enfeeble/Freeze), and who gets a second chance (ranged revives). Master those levers, and you’ll feel the whole lobby relax. Your DPS will thank you with faster clears; the wipe timer will show up a lot less.
If you only remember one checklist: Sanctum early, Grenade on chokepoints, LF‑85 tagging always, KH‑380 for emergencies, shoot‑revive instead of die‑revive. That’s the loop that wins Killing Floor 3 on hard maps.
Happy healing—and may your Sanctums always be in the right place.
