Achilles Armor

Hello I would like to know how do I can achieve the achilles armor, i have no idea con how to achieve it and I would like to…

Join a spartan company. That spartan company must have all of their kill commendations up to level five so you can recieve a rew pack with the full set

To unlock Achilles armor, you need to join a Spartan Company that has not already unlocked the Achilles armor. When that company maxes out level 3 for all Kill Commendations (level 5 for the helmet), the whole company will get the Achilles armor. Any people who join the company after Achilles is unlocked will not get the armor.