Sadayo Kawakami is a character and a hero from Persona 5. And she is also a teacher in the Shujin Academy, and in the Legacy of Chris Thorndyke, she was called in by Sojiro that she was once part of the Phantom Thieves as "Madame", and she must've realized that day that being a Phantom Thief was like the glory days, but once that Shido rose to power, she must've realized that would make Akira angry, and in the battle, she, along with Yuuki, and Ann fights against Kamoshida to save Tokyo.
She is reprised by Michelle Ruff in the English dub and Mai Fuchigami in the Japanese dub.