From Halopedia, the Halo wiki
Suicide Jiralhanae are a specialised type of Jiralhanae employed by the Banished.
Suicide Jiralhanae are a variation of the standard Jiralhanae employed by the Banished. Upon death, they explode, damaging enemy forces in the radius.
Suicide Brutes used similar weapons used by Banished Brute with the most unique weapon is the explosive armor that they use to explode violently upon death.
Suicide Jiralhanae are assigned to a group of Suicide Grunts that appear in the Blitz multiplayer mode of Halo Wars 2 as a playable card for all Banished leaders. Unlike it's multiplayer counterpart, the Suicide Grunts are equipped with Plasma pistols.
The Suicide Grunts are classed as anti-infantry, and performs well against infantry, vehicles and aircraft.