Tokugawa Sen ( ) is the princess of the original Tokugawa House that ruled Mikawa. Because she greatly enjoyed fighting, she was nicknamed "Princess Battle" ("", pronounced as "senhime", which is the same as "" or "Princess Sen").
When the Youkai racoon dogs conquered Mikawa and took over the Tokugawa House, forcing all humans to serve them, Sen refused to obey and kept fighting. Out of fear against her, the racoon dogs locked her up in the Mikawa dungeon.