Benjamin Tennyson also known as Ben Tennyson is the weilder of the Omnitrix and Ultimatrix and is the guide starter and united leader of the two teams and guides you through training which is optional. Notice he has an Omnitrix/Ultimatrix symbol on his chest.
His suit is called the Ben 10 Prototype Suit. It was added during the Birthday Celebration event for both factions and is now avalible for purchase in the hangar, costing at 500 credits. The Atlas Brigade version is known as Ben 10 Atlas, and the Banzai Squadron version is known as Ben 10 Banzai. They both have different Weapon Mods.