Kenseijo Adel No Yarinaoshi summary:

Hailed as the hero for leading his country to victory from a great war, the blind Sword Saint Adel is now in despair. Unfortunately, he failed to protect his benefactor, Princess Euphinea, whom he dedicated his entire life to. "I want to meet the princess once again," he muttered, wishing deeply that his prayers would be answered. A mysterious being, having heard his plea, granted his prayers, and he was sent back to the past, to a time when the princess is still alive. Unexpectedly, the Sword Saint (♂) has been transformed into a super-duper cute Sword Saintess (♀), and her heroic tale of unrivaled power will once again take place.