Jewel Plummer Cobb was a professor of biology and zoology, and was president of California State University at Fullerton from 1981-1990.
unsullied. 1  not soiled, untarnished: an unsullied public persona. 2  virginal; pure: He wears a purity ring signifying that he will remain unsullied until marriage.
You answered your own question. The queen only has so many Unsullied as her personal guard. The remainder are either off shift work or patrolling the city & guarding officials, etc. The Unsullied are an army, not a guerrilla fighting force as the Sons are. As we have seen since the U.S. Civil war, a guerrilla insurgency is effective when targeting specific individuals or groups.