Soon, he had a chance to show his skill in the defense of Sran Outpost. Because of his merits, he was promoted to officer, and became a respected tactician in the Alliance. However, he preferred to continue using the standard fleet trooper uniform.
He was then transferred to the Alliance High Command on Dantooine, where he would study tactics under expert Lieutenant Colonel Beryl Chiffonage. Chiffonage was known to teach him the Dsalisn Theories on low-atmosphere combat and the urban tactics used on Thyrsus.
General Jan Dodonna also took an active intervention in Credal's training. Credal often unofficially discussed with Dodonna and Vanden Willard about the tactics used in Yavin; and during the pre-meeting sessions, Chiffonage and General Airen Cracken retold him tales of old, which he enjoyed.
In a more active role, he was sent on missions with high-ranking members of the Rebel Alliance such as Dodonna, Willard, Crix Madine, Carlist Rieekan, Gial Ackbar, Pashna Starkiller and Adar Tallon. He also helped to develop Attack Pattern Delta.
One day, while he was supervising a patrol on Anoat system, he jumped to hyperspace without a warning, and effectively disappeared. His friends were reluctant to admit the possibility of him being a traitor, but they were forced to admit that he could be. Chiffonage wanted him to return so he could scold him, and then the two could be friends again.