 The Mark XXVI is described as capable of true independent strategic planning, while the final standardised Bolo, the 32,000-tonne Mark XXXIII is described as fully self-willed and able to operate indefinitely without external support.As humanity spreads beyond Earth, Bolos are used to protect first "the Empire", and then the "Concordiat of Man".For millennia, each successive mark of Bolo proves to be the lynchpin of humanity's ground-based defenses, especially in the numerous and protracted wars against various aliens, most notably the "Deng" and the "Melconians" in the 30th century.