Specializations will play a big role in Halo 4. This new addition to the series behaves much like classes do in other first-person shooters and allows you to (as the name suggests) "specialize" in a certain character class if it suits your style of play.
These Specializations provide ten extra levels for you to attain, and are unlocked once you max out at level 50. They allow you to be in more control of your Spartan and accentuate your personal playstyle.
Each Specialization has ten levels, and once you select a Specialization, you'll have to level it up before you can try out something else. Once you've completed a Specialization, it'll be available to you—unlocks and all—for use whenever you want.
Completing each Specialization will provide you with the following unlocks:
The Armor Mod is attained at level 10 of the Specialization and is the defining unlock for each Specialization.
The Wetwork Specialization is essentially the Halo universe’s equivalent of a stealth operative. Wetwork prizes stealth and ranged kills over close combat encounters.
Unlockables:
This Specialization allows you to gain an edge over your opponents by gaining more experiential data from each encounter, effectively earning ranks faster than anyone else.
Unlockables:
The Engineer allows you to predict when and where ordinance drops are made, essentially providing you with an ordinance radar. Beat your enemies to the punch and scope out all the ordinances before they do.
Unlockables:
The Tracker's armor mod allows you to get the most out of ordinances, by recalling your current ordinance to request a new one.
Unlockables:
The so-called Rogue increases your stability while aiming, and prevents you from losing your aim while being shot at in zoom mode.
Unlockables:
The Nemesis armor mod provided to the Stalker allows you to effectively track the last person who killed you throughout the entire map. They'll regret messing with you.
Unlockables:
The Pathfinder is geared towards getting the most out of mounted weapons. With the Gunner Armor mod, all mounted weapons will cool down faster when overheated. Your movement speed is also increased while carrying a detached turret weapon.
Unlockables:
Last, but not least, the Operator is the specialization to go for if you're a dedicated driver or vehicle pilot. The Wheelman Armor mod gives your vehicle additional resistance to damage and provides your enemies with a decreased amount of time in which they may hijack your vehicle.
Unlockables: