The "Least of the Bayushi" letter is a sealed document found among historical records pertaining to the Battle of the Snow Plains. Addressed to "the least of the Bayushi," it condemns the recipient as a shame and failure unworthy of rewards. The letter calls for the recipient to seek forgiveness from Bayushi and perform penance, stressing that nothing will be granted without merit and that the recipient should not expect what they have not earned.
During court proceedings, the letter was presented as a historical artifact after being retrieved from a sealed jar that had remained untouched for at least three centuries. Upon its reading by Katsuki Kage, the presiding magistrate, Bayushi Monban visibly reacts with shock, as he is speculated to be the intended recipient. The letter's contents deeply affect Monban, prompting him to leave the court in distress after claiming sole credit for protecting the divine couple. Katsuki Kage subsequently acknowledges the letter's historical significance while refocusing on other documents related to the case.