From Halopedia, the Halo wiki
Armageddon is a multiplayer medal in the Halo 5 Multiplayer Beta. It is believed that it is awarded to a player once they get 4 kills with the rocket launcher without dying. This medal is not present in the final game.
- Youtube.com Halo 5: Guardians Beta - Armageddon (film clip)In this film clip, a player is awarded the Armageddon medal after getting 4 kills with the rocket launcher in a row without dying.