When Conan returned to Tarantia after escaping from Xaltotun, Valerius was still in controll of Aquilonia. Valerius was planning to execute the Countess Albiona, but Conan saved her. When saving her he was discovered by Valerius' guards, and had to run. Hadrathus and some other followers of Asura helped Conan escape.
When Conan had gotten hold of the Heart of Ahriman, Hadrathus, along with Zelata, was the ones that met Xaltotun at the King's Altar and used the heart's magic against the wizard to banish him again from the world.