The Saint's Magic Power is Omnipotent (Light Novel) Vol. 2 (Kobo eBook)
Grand Magus Yuri Drewes has risen from his coma, and he wants to teach Sei how to wield her magic. Just one problem: Yuri definitely suspects Sei's the Saint, but Sei's not ready to be outed. Even worse, under Yuri's tutelage, Sei's power continues to grow, and soon her true strength may be impossible to conceal.