Recruit
From Halopedia, the Halo wiki
Recruit is a Halo 3 Xbox Live multiplayer rank.[1]
It is the lowest rank and is succeeded by the Apprentice rank
This rank is essentially an introductory rank for when you first start playing Halo 3 online. This rank is represented by a bronze, hollow diamond, and is promoted to a higher Enlisted rank after achieving one more Experience point.
Some players are able to skip this rank, if your skill is increased high enough or if you play a Double EXP Weekend on your first game, yet this is only a prediction for it isn't precisely known. This may also be able be done by doing exceptionally well in the Basic Training playlist that first unlocks when you start Matchmaking.
You may also get achievements in Basic Training, as it counts as a Ranked free for all match.
Obtaining Rank
