I Reincarnated as the Great Demon King

As the saintess with the strongest affinity for the element of light in a thousand years, how did she suddenly become the legendary Demon King who commits every imaginable evil? But this Demon King is nothing like the fearsome figure of legend. Her magic is depleted, and she's been trapped in this palace the whole time. With no other choice, she has to return to her old line of work. So she pretends to be weak, helpless, and pitiful, tricks the people from the Holy Temple who come to investigate, and even infiltrates the saintess selection. But after leaving the demon palace, she discovers that stories about her are everywhere in the kingdom. The people of the Holy Temple are spreading the tale that she fought the Demon King to the death and ultimately gave her life for the God of Light. Yisel: ??? How does she not remember doing anything so heroic? Now that she's mixed in with the next generation of saintess candidates, she has no idea which secret identity she should protect. Theme: Perseverance is a wonderful virtue.