I Went Looking for My Sister from the Start, but Found the Strongest Witch Instead

In year xxx3 of the Old Calendar, the war to hunt down the witches changed the balance of power across the world. The ancient witch clan was nearly wiped out... In 999 of the New Calendar, Kyle returned home from hunting to find that everyone in the village had vanished, including the sister he had relied on for company... “Little sister, where are you...” One day, a sleeping girl opened her eyes in some ruins. After her long slumber, she knew nothing about her past... “Who am I...”