As the sets progress so does time, you'll see old characters in new forms. Great examples since they are obvious are Zombie Lord / Zugateroza >>> Undead King / Zugateroza; Holy Emperor / Retear >>> True Holy Emperor / Retear; Saber Saint / Lapierre >>> Holy Knight / Lapierre. Also expect to see other units grow up in a since like Zagar!
"While Retear in his previous state was certainly powerful, we felt that his skill set was not particularly satisfying to use..." A.K.A. he was too Refess for Refess.