Lady Mamiya (間宮夫人 Mamiya Fujin) is the main antagonist and final boss of Sweet Home. When the crew first arrive at the mansion, the ghost of Lady Mamiya appears before them and seals off the exit.
Spoiler Warning: Significant plot details follow.
Lady Mamiya was the beloved wife of Ichirō Mamiya. In 1959, thirty years prior to the events of the game, her two-year-old son accidentally fell into a furnace. Distraught by her loss, she began to go insane, kidnapping other children and throwing them into the furnace so that her son could have "playmates". After being caught red-handed by local villagers, she committed suicide in the same furnace. Her furious spirit now haunts Mamiya Mansion, attempting to either kill or drive off anyone who goes near her son's grave.
End of Spoilers.
The fight against Lady Mamiya is unique in that you do not simply attack her until her HP reaches 0. Instead, the following procedure must be followed:
- When she says, "I will kill you all! Die!!", use the Tool.
- When she says, "Go away!! Begone from here!!", use the Photo.
- When she says, "Wah!!", have the party pray. After this, she will transform.
- Keep attacking her until the screen flashes white (around 500 HP), then use the Diary.
- Have one character pray with at least 50 Pray Points.
- Attack again until the screen flashes white (another 500 HP), then use the Coffin.
- Have one character pray with at least 80 Pray Points.
After this, Lady Mamiya will be defeated and leave the mansion, now at peace.