The Clan of the Cats (Horseclans, #18)

THE HUNTER When Milo Morai, the Undying High Lord, and his Horseclans warriors found the tower ruins, they welcomed it as the perfect citadel from which to hold off the packs of ravenous wolves eager for their blood. But the ancient building hid a secret far more dangerous than either wolves or any human foe, for in its depths waited The Hunter - the penultimate product of genetic experimentation gone wild, one of the few descendants of a powerful breed that had long outlasted its human creators. The Hunter - who, with fang, claw, and blood-chilling speed would challenge the Undying Lord himself to a battle to the death! Milo Morai and his Horseclans warriors take refuge from preying wolves in the ruins of an ancient tower, where they encounter The Hunter, a genetically-engineered creature determined to challenge Milo Morai in a battle to the death