As you have been fervent believers of the Lotus Sūtra, you now beckon the major sins committed in the past in order to lessen its karmic retribution. For instance when iron is forged well, its flaws become visible. When burned, a stone turns to ashes, but gold becomes pure gold. I am sure the merit of your true faith in the Lotus Sūtra will be evident, and the ten female rākṣasa demons, guardians of the Lotus Sūtra, will protect you now. Just as Indra appeared as a rākṣasa demon before Young Ascetic in the Snow Mountains to test his resolution and Vaiśravaṇa disguised himself as a dove to test King Sivi, the ten female rākṣasa demons may have possessed your parents in order to torture you and test your faith. You may regret if you are not steadfast in your faith. An overturned cart is a warning for the cart that follows.

Kyōdai-shō, A Letter to the Ikegami Brothers, Writings of Nichiren Shōnin, Volume 6, Followers I, Page 77-78