Archimonde is guarded by three of his lieutenants from the Hyjal Summit raid from the Burning Crusade expansion: Anetheron, Kaz'rogal, and Azgalor. These mini-bosses retain the abilities they used in the Battle for Mount Hyjal.
Anetheron will occasionally crowd-control players with Sleep, casts Carrion Swarm which debuffs all players struck by the effect, and will Summon Towering Infernal. TheTowering Infernal stuns nearby players with Impact when it lands and will damage nearby players with Immolation.
Kaz'rogal has a powerful Cleave, will stun nearby enemies with War Stomp, and will affect casters with Mark of Kaz'rogal, draining their mana and causing heavy damage to nearby players when their mana runs out.
Azgalor also has a powerful Cleave, will cast small Rain of Fire patches on targeted players, and will debuff random targets with Doom. After 20 seconds, players marked by Doom will die, summoning a Lesser Doomguard. The Lesser Doomguard debuffs random players with Cripple.
While these enemies are not particularly challenging, the optimal order to kill them in is Anetheron > Azgalor > Kaz'rogal. This quickly removes the AoE Sleep and Carrion Swarm abilities as well as both add-summoning enemies.