The Avatar of War (Rallos Zek) is found inside Zek The Orcish wastes just outside the gates of Deathfist Citadel. As you begin the battle he will immediately call a hellhound dog to his aid which seems to be impervious to damage, but must be offtanked. Ontop of this he will routinely call upon orc raiders to his aid which have 4-7 in a group. They are all level 84-85 heroic ^^^ mobs with nasty single target and AoE target attacks (presumably).

Rallos is a berserker class by nature and has alot of abilities that will cause him to do spike damage. It is best to have a class that can cast stone skin or life saves quickly to absorb the damage spike attacks. Rallos is considered a middle ranged hard Avatar mob, but isn't as difficult as Disease or The Avatar of Justice.