How to Beat the Brumak in Gears of War: E-Day – Act 1 Boss Guide
A quick strategy for beating the Brumak at the end of Act 1, Chapter 4 in Gears of War: E-Day and unlocking The Bigger They Are.

The Brumak fight at the end of Act 1, Chapter 4 – Back in the Fold is mostly about maintaining space and refusing to get trapped near the Courthouse.
Defeating it unlocks The Bigger They Are… achievement.
Brumak Strategy
The safest approach is simple: keep moving around the arena and fight from range.
The Brumak uses the long chains attached to its wrists to punish you when it gets close. If you stay in one corner for too long, it can close the distance and leave you with very little room to escape.
Best Weapons for the Fight
Longer-range weapons are easier to use here because they let you keep damaging the Brumak while rotating around the arena.
A Lancer or Hammerburst works well for steady damage. You can also find an explosive launcher in the arena that can deal much heavier burst damage when you have a clean shot.
Keep an eye on the extra ammunition placed around the fight instead of trying to finish the entire encounter from one position.
Deal With the Smaller Enemies
As the Brumak loses health, additional small Locust enemies begin entering the arena from emergence holes.
Do not ignore them. They can interrupt your movement and are especially dangerous if they force you into the Brumak's path.
Clear the nearby enemies, create space, then return your attention to the boss.
The Main Mistake to Avoid
Do not stay on the Courthouse steps and try to tank the fight from one location.
Use the full arena. When the Brumak pushes toward you, rotate to the opposite side, rebuild the distance and continue firing.
Once it falls, The Bigger They Are… should unlock as part of the Act 1 progression.
If you are cleaning up the same chapter, check the Act 1 Collectibles guide before moving into Act 2.