TvT Mass Reaper

General Overview

This mass Reaper build order gets 2 Reactored Barracks cranking out 4 Reapers at a time in order to overwhelm your opponent with purely mass Reaper.

Build Order

  • 12 – Refinery
  • 13 – 1st Barracks
  • 15 – 2nd Barracks
  • 17 – @100% 1st Barracks, start Reactor on 1st Barracks and 2nd Refinery
  • 17 – Orbital Command and Supply Depot
  • 17 – @100% 2nd Barracks, start Reactor on 2nd Barracks
  • @100% Reactors, start constant Reaper production
  • Push out when your first 6 Reapers finish (@5:25ish) with 20 SCVs at home.


There is minimal SCV scouting with this build because you will open the same regardless of what your opponent is making.  The majority of your scouting comes from your constant Reaper attacks.

Against anything but Banshees, constantly produce Reapers to overwhelm your opponent.  Against Banshees, be sure to cancel your Reaper production and start producing 4 Marines at a time.  If you have done significant economic damage, then getting an Engineering Bay for a Missile Turret is not a bad idea either.


This build actually transitions pretty well into a decent midgame for being an all-in.  However, you can only transition into Bio after opening with this build because it is hard to utilize your quick Reactors and two Barracks early on if you are trying to transition into Mech.  When you feel like you cannot do any more damage with your Reapers, be sure to stop Reaper production and begin your Bio upgrades.

For a standard Bio follow-up, get your natural expansion, start Marine production, and get a 3rd Barracks with a Tech lab.  This way you can start Stimpack, an Engineering Bay, Factory, and 3rd Refinery all at the same time just like as if you had opened with a normal 1rax FE into Medivacs.

For a fast upgrade transition, start your natural expansion, Marine production from the 2 Barracks, 2 Engineering Bays, and then +1/+1.  As soon as you can, get one more Barracks with a Tech lab so that you can start researching Stimpack.  Then, you can take your third Refinery and get a Factory to go into Reactored Medivacs and +2/+2.

For a follow-up timing attack, start your natural expansion, Marine production, and a Factory instantly.  Get a Tech lab on the Factory and start Siege Tank production in order to hit a very fast Marine/Tank push with your second Siege Tank.  Behind this contain/attack, you can get your 3rd base, 3rd and 4th Refineries, double Engineering Bays, and 2 or 3 more Barracks (get Stimpack and Combat Shields).


As soon as your first Reapers pop, start being aggressive.  Your number one goal is to deny your opponent’s Factory for as long as possible (Hellions or Widow Mines can be difficult to maneuver around), but in order to do this, you have to be in your opponent’s face with your Reapers as soon as they are built.  Also, with your constant harass, be sure to dwindle your opponent’s Marine count without committing too hard and losing any Reapers.

Your Reaper count increases very quickly, and when you get around 6 to 8 Reapers, you can truly overwhelm most units your opponent can have.  Thus, focus on killing his army with your initial Reapers–you will be able to kill his SCVs once his army is dead.

In general, if your opponent sees what you are doing, you are in trouble.  Thus, it is suggested that at least one of your Barracks is build outside your base (even just at your natural will sometimes work fine).  However, you can proxy both Barracks outside your main to make this build a little more all-in too.  This also works for some mind games because if your opponent scouts you with a Refinery but no Barracks in your main, he will most likely try to defend proxy Marauders (a defense that is awful on most maps against mass Reaper).

Pros and Cons

This build is very aggressive and can catch many opponents off-guard.  With a hilarious amount of Reapers, you are usually able to overwhelm their army within the first 8 minutes.  However, even if the all-in does fail, it can still transition into a 11-12 minute Bio+Stimpack/Medivac timing.

However, if you do not do much damage, you will be quite behind your opponent in tech (and possibly income).   Also, this build can be easily scouted if an SCV sees both Reactors building before a single unit, so at least one of the Barracks must be proxied outside of your main.

Favorable Maps

This build is best on maps where you can Reapers can jump in and out of the main far away from the main ramp for obvious reasons.

  • Catallena
  • Foxtrot Labs
  • Nimbus


Mass Reaper Tutorial Replay vs a Very Easy AI

Written by Virus