Our "Eternal Mentor" is mentioned hundreds of times in the Lotus Sutra and writings of Nichiren. How about yours?

"This secret Law of Shakyamuni Buddha, the lord of teachings, was not entrusted to Universal Worthy or Manjushrī, bodhisattvas who are widely known in the three existences of past, present, and future, much less to any being of lesser importance. It follows, then, that the ceremony in which the Buddha expounded this secret Law differs from those in which he preached the four flavors and three teachings, and the first fourteen chapters of the Lotus Sutra, which embody the theoretical teaching.

The place where the ceremony occurred was the eternally existing Land of Tranquil Light. The lord of teachings who abided in this land was the Buddha eternally endowed with the three bodies, and those whom he converted had to be of equal status. This being the case, from the depths of the Land of Tranquil Light he summoned up Superior Practices and the others who make up the four bodhisattvas, original followers of the Buddha who since the remote past had praised [the Buddha and the original Law], and entrusted this doctrine to them. As the Discipline Master Tao-hsien says, “The Law embodied therein [in the Lotus Sutra] is the Law that was realized countless kalpas in the past, and therefore it was entrusted to persons who had been the Buddha’s disciples from countless kalpas in the past.”