Tech is Clone Force 99's engineer and pilot, enhanced for exceptional cognitive processing. He is voiced by Dee Bradley Baker, who gives him a clipped, faintly impatient delivery quite unlike any other clone in the franchise.
He is the squad member the series uses for exposition and, increasingly, for its emotional ambushes. Tech states difficult things plainly because the alternative does not occur to him — that the clones were designed to be expendable, that Crosshair's behaviour is explicable, that a plan has a low survival probability — and the show gradually reveals that he has understood the feelings all along and simply files them elsewhere.
His death at the end of the second season is the point at which The Bad Batch stops being a picaresque. He lets go deliberately, having calculated it, and the third season is largely about a squad that no longer has anyone to explain things to them.