Grand Master Chang-an states in his Annotations on the Nirvana Sūtra, “The one body of the Buddha is equipped with the three virtues of the lord, master and parent.”

The Lotus Sūtra, chapter 3 on “A Parable” preaches:

“This triple world (realms of desires, form and non-form) entirely belongs to Me (the World Honored One, the most venerable in the triple world, whose domain consists of 25 regions in the triple world or the six lower realms of the dharma world—four continents, lower four realms, six heavens in the realm of desire, Great Brahma Heaven, four meditation heavens in the realm of form, four heavens in the realm of non-form, the non-thought heaven, and heaven of not returning). The people in them are all My children (children of Dharma-nature who established the bond with Śākyamuni Buddha in the eternal past; the Words and Phrases of the Lotus Sūtra, fascicle 5, explains this, “All people are equally equipped with the same Buddha nature, so they are equal children of the Buddha”). Nevertheless, this world is full of troubles and difficulties. I alone can save all living beings.” The Profound Meaning of the Lotus Sūtra, fascicle 6, explains this, “Properly speaking, all living beings will awaken aspiration for Buddhahood by following this Buddha, and proceed to Buddhahood following the Buddha without falling back to a lower spiritual stage.

Thus it is Śākyamuni Buddha alone who is equipped with the three virtues of the lord, master and parent.

Ichidai Goji Keizu, Genealogical Chart of the Buddha’s Lifetime Teachings in Five Periods, Writings of Nichiren Shōnin, Doctrine 3, Page 245-246