A Quiet of Stone — Stephen Leigh

Gyll Hermond was spawned in the dark streets of Neweden, a world torn apart by intrigue and blood-feud. He'd molded a ragged band of kinless outcasts into a trained killing force -the Hoorka Assassins' Guild- only to be deposed as leader in a bitter struggle for power. Now Fate brings Gyll back to Neweden as military commander of a powerful Trading Family.