Gunslinger Girl -Il Teatrino-

The girls of the Social Welfare Agency are no ordinary children. They are the grisly remains of human wreckage pieced back together with cybernetic implants and trained to kill by the government.

The oldest, Triela, pursues her targets with a ferocious enthusiasm, unwilling to settle for less than total annihilation. Her mirror in this bloody stalemate is Pinocchio, a shell of a boy raised as an assassin by the FRF: a terrorist faction at war with the SWA. Cold and cruelly efficient, he wields sharpened steel as though it were an extension of his own hand.

Once human, these shattered souls have become murderous machines with only vague recollections of what it meant to be real — and a brutal compulsion to be the last killer standing.

(Source: Funimation)