UNSC Spartan is a Halo 3 Multiplayer Achievement. This achievement is earned when the player earns 12 EXP in any one playlist on Xbox Live. This Achievement gives 15 Gamerpoints to the player and unlocks the MJOLNIR Mark V Armor Permutation for use in anything Multiplayer, combat-related. The Mark V armor is not awarded by becoming a Sergeant, only getting this achievement. The Achievement is not awarded by the global ranking, only the individual playlist ranking system.
It is represented by a gray plate with an eagle holding a gold thunderbolt on the right side and three gold arrows on the left, which is the Spartan insignia.
- The insignia representing the Spartan, which is an eagle carrying a thunderbolt and three arrows is identical to that of Zeus, a god in ancient Greek mythology.
- Above the eagle logo is the symbol used in the game Marathon.
- Occasionally, if a player skips enough ranks too quickly, they will bypass the achievements' criteria, and are unable to ever unlock the achievement, even with the help of EXP loss to lower one's ranks.