Look: Thomas wears a suit of Mjolnir Powered Assault Armor/Mark V, resembling this piece of concept art:
The green plating is instead a shade of blue, the visor is silver in color, and the cloth around his neck is black.
Under the helmet, Thomas has unusually pale skin, with brown hair that's noticeably beyond regulation length, and green eyes. He possesses a thin, haggard build that's mostly hidden by the bulk of his armor.
Weapons: Thomas is a master of close-quarters weaponry. There are few that even come close to his level of proficiency... however, a critical logistics error resulted in him being currently equipped with an M6 Spartan Laser, and an SRS99D-S2 AM sniper rifle, neither of which he is particularly skilled with. He also has two knives stowed in his pauldrons.
Bio: A SPARTAN-III deployed to assist UNSC forces on the Halo ring in question against a Covenant assault, Thomas is sure that the job would be a heck of a lot easier if he'd actually been given the right set of tools for the task. His inexperience with his current loadout turns every firefight into a tedious, frustrating endeavor, and he's about as useless as a SPARTAN could be- a sad reality that only adds to his anguish.