Jiralhanae Major
From Halopedia, the Halo wiki
Brute Major is an elevated rank for Brutes of the Covenant. These veteran Brutes are stronger and smarter than their younger counterparts, and have been given the right to wear basic armor. This armor also makes them harder to kill.
Combat
These brutes usually carry Brute Plasma Rifles, Covenant Carbines, and Brute Shots. They are usually seen commanding less experienced Brutes, and they are more aggressive when Berserking. It is best to try and kill them using a Beam Rifle, Sniper Rifle, or their own weapon: the Brute Shot. Also, like most of the enemies, Brutes are vulnerable on their back and will be killed by one hit from almost any weapon. This is especially useful when using the Arbiter's Active Camouflage in Halo 2