Martin Bradley may believe the following but not Nichiren Daishonin

"The Guardian Deities and the Spirits of Good (shoten zenjin) in our teaching are the psychic forces that prevent us from making very regrettable mistakes or doing the wrong thing. Nevertheless, they are all forces that exist in our own heads and are to be found nowhere else." -- Martin Bradley

Really?

Nichiren teaches, quoting the Benevolent King's Sutra"

Though this sutra exists in the nation, its ruler has never allowed it to be propagated. In his heart he turns away from it, and he takes no pleasure in hearing its teachings.... In the end, he makes it impossible for us [the four heavenly kings] and the other countless heavenly beings who are our followers to hear this profound and wonderful teaching. He deprives us of the sweet dew of its words and cuts us off from the flow of the correct teaching, so that our majesty and strength are drained away.... And once we and the others abandon and desert this nation, then many different types of disasters will occur in the country, and the ruler will fall from power."

He also teaches the following:

"At that time, because the innumerable benevolent guardian deities will be unable to taste the flavor of the Law, their majesty and strength will diminish."

"And in addition, the Buddhas of the six directions and the twenty-five bodhisattvas of the Pure Land school, the twelve hundred honored ones of the True Word school, and the various honored ones and benevolent guardian deities of the seven schools are also certain to protect Nichiren."

"Third, it would appear that the guardian deities have deserted this country, and this is probably one reason why offenders do not suffer any immediate punishment."

"When one comes to the end of one’s good fortune, no strategy whatsoever avails. When one’s karmic rewards are exhausted, even one’s retainers no longer follow one. You survived because you still have both good fortune and rewards. Moreover, in the “Entrustment” chapter,1 theheavenly gods and benevolent deities pledged to protect the votaries of the Lotus Sutra. Of all the guardian deities in heaven, it is the gods of the sun and moon who visibly protect us. How can we doubt their protection? The heavenly deity Marīchi in particular stands in service before the god of the sun. When the god of the sun protects the votaries of the Lotus Sutra, how could the honorable one of heaven Marīchi, who is his vassal, possibly abandon them? The “Introduction” chapter of the sutra reads, “[At that time Shakra with his followers, twenty thousand sons of gods, also attended.] There were also the sons of gods Rare Moon, Pervading Fragrance, Jeweled Glow, and the four heavenly kings, along with their followers, ten thousand sons of gods.” Marīchi must be among the thirty thousand sons of gods who were present at the ceremony. Otherwise, this deity could only abide in hell.

You must have escaped death because of this deity’s protection.Marīchi gave you skill in swordsmanship, while I, Nichiren, have bestowed on you the five characters of the title of the Lotus Sutra. There can be no doubt that Marīchi protects those who embrace the Lotus Sutra. Marīchi also upholds the Lotus Sutra and helps all living beings. Even the words “Those who join the battle are all in the front lines”derive from the Lotus Sutra. This is what is meant by the passage “If they should expound some text of the secular world or speak on matters of government or occupations that sustain life, they will in all cases conform to the correct Law.”3 Therefore, you must summon up the great power of faith more than ever. Do not blame the heavenly gods if you exhaust your good fortune and lose their protection."

"Third, it would appear that the guardian deities have deserted this country, and this is probably one reason why offenders do not suffer any immediate punishment."

It is obvious that Nichiren believed in and taught the very real existence of heavenly beings, Buddhist gods, and guardian deities. More importantly, Nichiren, unlike Martin Bradley, the Nichiren Shoshu, and the Soka Gakkai, believed in the very real existence of Shakyamuni Buddha of the Juryo Chapter of the Lotus Sutra or the Eternal Buddha