Gears of War: E-Day Horde Siege Invasion Events
Corpser and Brumak bosses, three-squad callouts, and how to extract after the event.
Horde Siege is not only wave defense. During a run on Golden Quarter, the instance can fire an Invasion Event — a map-wide boss beat that pulls all three squads of four onto the same threat. The August Open Beta includes two Invasion bosses: Corpser and Brumak. Launch Horde expands the roster; treat the beta pair as the teaching set before October 6.
This page is the callout sheet: when an event starts, who shoots what, how R.I.G. timers still matter, and how to reach the Raven without wasting Weapon Parts. Read it next to Horde Siege, Golden Quarter, Siege Classes, and How to Extract. The August 12 hit-detection pass makes focus fire more trustworthy than it was in Early Access — see the Weekend 2 patch.
What an Invasion Event is
A normal Horde Siege mission assigns each squad its own R.I.G. work: Secure, Calibrate, Repair, Defend, or a Horde wave at a node. Squads crisscross Kalona streets, grab Supply Caches for Energy, and optionally peel for Secondary Objectives. An Invasion Event interrupts that split. A Corpser or Brumak (or the event’s scripted path) becomes the shared problem. Preview sessions described these beats as the moment three fireteams have to look at the same lane.
The beta is a subset: two bosses, one map, class levels capped near 10. You will not see the full launch Invasion list here. You will see the same discipline launch expects — call the boss, freeze bad secondaries, and do not let an unattended R.I.G. fail while everyone tourist-shoots the monster.
Corpser — underground pressure
The Corpser is the emergence-horror beat: a large burrowing Locust that turns streets into temporary death zones and punishes players who stand on the same cobbles they used for a calm Calibrate. Treat it like a moving E-Hole plus a tank.
What to do
- Marksman marks and holds weak points with the Pulse Drone. Call the body part and the street name from Golden Quarter — “Corpser, market steps, dorsal” is enough.
- Assault uses Sonic Disruptor when the Corpser commits to a lane so the front line can dump magazines without eating a sweep.
- Breacher saves Adrenaline Injector for exposed windows, not for the first roar. Gut Puncher and Incinerator punish clustered Drones that spawn around the boss; do not waste explosives on armor that is still closed.
- Medic plays one building back. Invasion area attacks create simultaneous downs. COG tags still drop — a hero revive in the open usually feeds the Corpser a second kill.
Campaign instincts from How to Close E-Holes transfer: you still collapse spawn lips, you just do it while a boss owns the intersection.
Brumak — the walking siege engine
The Brumak is the heavy-weapons beat. It wants space, long sightlines, and panicked squads that abandon Repair channels to spray the legs from twenty meters with Gnashers.
What to do
- Split damage and objective. One squad (often the one already on Defend) stays on the active R.I.G. if the timer is red. Two squads take the Brumak.
- Marksman owns the gunner / head profile. Longshot and Pulse Drone are the cleanest tools; the August 12 Horde hit-detection improvement helps here more than any other fight.
- Assault and Breacher cut escort Drones and Boomers first. A Brumak with a full escort deletes Medics.
- Save Energy. Stim Vaporizer and Sonic Disruptor win the last third of the event. Empty bars at the roar are how extracts fail five minutes later.
If your class kit includes the Prototype Lancer, the August 12 base-damage buff makes sustained fire more honest; you no longer need a perfect Active Reload on every mag to chip a Brumak. Perfect reloads still help — they just are not the only damage plan. Weapon Mods remain Horde-only; do not expect those attachments in Versus.
Three-squad script (say it out loud)
| Phase | Caller | Line |
|---|---|---|
| Event warning / spawn | First visual | Boss name + landmark |
| Escort clear | Assault lead | “Escorts first” |
| Weak point up | Marksman | Body part + “burn now” |
| R.I.G. still dying | Any squad on the node | “Stay on Repair / Defend” |
| Event down | Any lead | “Back to nodes, then Raven” |
| Extract | Any lead | Pad letter / street — see How to Extract |
Voice beats pings on a twelve-player instance. Random matchmaking can still win if one player repeats the table above. Parties that already run Bravo Squad co-op nights usually need fewer words.
Difficulty, playlists, and when events hit
Blitz (about 15–20 minutes) may only give you a short Invasion or none — it is the playlist for learning streets. Siege and full Horde (up to about 50–60 minutes / ten waves) are where Corpser and Brumak show up as the run’s midpoint or finale. Infantry is the Crush the Bug extract tier; you can learn events there. Commander and Allfather assume you already split damage and R.I.G. without a speech.
Modifiers from official Horde messaging — poisons, explosive Drone deaths, perfect-reload-only rules, friendly fire — can stack on top of an Invasion. If a modifier forbids sloppy explosives, Breachers switch to controlled Gut Puncher timings instead of panic Incinerator sprays.
After the boss: extract is the score
Killing the Invasion target is not a win screen. Weapon Parts and a clean Crush the Bug extract still require the Raven. Players who chase leftover Drones across Golden Quarter while the pad is live are the reason squads miss the eight-extract reward. Bank the event, rotate, recover COG tags, and leave. Reward rules: Open Beta rewards. Progress between weekends carries; class and Player Level still reset at launch.
Related pages
- Horde Siege — R.I.G., Energy, playlists
- Golden Quarter — streets and pads
- Siege Classes — Assault, Breacher, Marksman, Medic
- How to Extract — Raven, tags, Crush the Bug
- Enemies: Locust & Feral — lesser targets around the boss
- Weekend 2 patch — Horde hit detection
- Guides Hub — full tutorial list
Frequently Asked Questions
Straight answers for Emergence Day prep and launch week.
Which Invasion bosses are in the E-Day Open Beta?
The beta includes two Invasion bosses: Corpser and Brumak. Launch Horde Siege adds more Invasion threats and two additional Horde maps beyond Golden Quarter.
Do all three squads have to fight the Invasion Event?
Yes for the boss itself, but one squad should stay on a failing R.I.G. if the timer is about to expire. Abandoning every node to tourist-shoot the Brumak loses the run.
Does killing a Corpser or Brumak extract the squad?
No. You still need a successful Raven extract to bank Weapon Parts and count Crush the Bug extracts. The Invasion is a midpoint, not the exit.
Which class is best for Invasion Events?
Marksman for weak-point damage, Assault for lane control, Breacher for burst windows, Medic for the double-down after area attacks. A full four-role squad beats four Assaults.
Did the August 12 patch change Invasion Events?
The notes do not add a third boss. They improve Horde hit detection and stability, which makes Corpser and Brumak focus fire more consistent than in Early Access.