El'Myamoto
Sub-Commander Myamoto (nicknamed "Darkstrider" and "He That Walks Unseen") is a loose cannon Tau Pathfinder who doesn't play by the rules, and is thus despised by most of his superiors for toeing (hoofing) the line between interpreting orders and flat-out ignoring them.
Darkstrider is currently the only named Tau footsoldier HQ, and one of their best field operatives, leading suicide mission after suicide mission, turning the tides of battle to the Tau's favour, and bring his men back into the bargain.
Also worth noting is that he is quite chunky for a Tau (or any non-Ogre in the Warhams, for that matter), being broadfaced and having a mouth that could rival a Slann.
tl:dr: He is Tau Empire's Commander Shepard.
History
Darkstrider was born on T'au, and worked his way into the Pathfinder squads as a Shas'la, before passing his trial by Fire, and being offered a position in a Crisis-Suit squad, an offer he scorned, wishing to stay with the Pathfinder squads that he had served with. As he gained notoriety, while serving as a Pathfinder Shas'ui, before passing his second trial by fire, and being offered a position leading a Stealth Suit squad, a choice he derided before returning to serve as a Pathfinder.
Time and time again Darkstrider has returned to the Pathfinder teams with which he originally served, leading his squads through thick & thin, bringing them through suicide missions against impossible odds. However, his attitude and almost complete dismissal of the repeated requests for his promotion to Shas'O rank have earned him numerous enemies among both the Fire Caste commanders and the Ethereals, only the vouching of Shadowsun keeps him on the front-lines where he can bring his talents to bear.
His constant refusal of command positions, and subtly dismissive behaviour has however, led to demands for him to either be retired, or removed, while other commanders value his ability to lead terror missions, and sudden raids with a skill that is rarely seen outside or inside the Tau Empire.
Tabletop
Darkstrider is the only named Fire Caste infantry character, and much like the Pathfinder squads he commands he is not a combat HQ, instead his unique wargear, and rules allow him to harass enemy unit with relative impunity. His special rule mean that after firing overwatch his squad may consolidate 1D6" away from the assaulting unit, and his personal wargear (the structural analyser) reduces an enemy units Toughness by 1 for the purpose of resolving wounds when any model from his unit makes a shooting attack. A solid addition to a Pathfinder Squad, especially if they're kitted out with Ion or rail rifles & a grav-inhibitor drone to make a fairly cheap assassin squad that while only be caught in the luckiest of charges.