Anyhow: Buddhist metaphysics. Possibly only rival to Christianity in depth of intellectual culture.
I actually learned Indo-Aryan languages in order to solve the question you pose, and still have no definitive answer.
Buddhist “ontological theology” simply has no name in the English language I know of actually useful in understanding.
What I can affirm, after studying the Pali canon, is that nothing morally unwholesome is promulgated, nothing anti-Christian in terms of moral theology. The morals of original Buddhism are utterly pure. Systematically, 1) all drugs and intoxicants, and the trafficking thereof, are outlawed, 2) all unchaste sexual misconduct (unnatural relations within marriage even–no compromising here) outlawed, 3) bearing false witness outlawed, 4) homicide absolutely outlawed as the self-destruction of one’s own soul, and 5) larceny, whatever form, either outright robbery or usury, thoroughly forbidden. The original Buddhist morality is untouchable.
Philosophically, Buddhism, in American terms, is the the polar opposite of Lockean empiricist sensualist materialism: in American terms, morally anti-nihilist, a form of moral objective realism. For the American mind, I suppose, something like Kantian-Coleridgean transcendentalist idealism and its morality of anti-utilitarianism is not without comparative value.
In medieval terms, “Ghibelline” in its *Kshatriya * aspect of warrior rebellion against superstitious priestliness, the Temple sacrificial blood-rites necessitating endless butchery of animals.
Mahavira and Buddha, in their own way, realized the Christian intuition: I desire mercy and a contrite heart (cardiognosis, penthos), the moral regeneration your ritualistic Temple-sacrifices are nothing but a symbolic shadow of…; your sacrifices of beasts, with hearts unchanged, are nothing but appalling…
Ethnologically, the fact of the Buddha’s heritage as an Aryan, Indo-European prince is not without significance. The Saka tribe he descended from, as “Sage of the Sakya” (Sakyamuni) is the Eastern offshoot of the same Indo-European nucleus of peoples, out of which the Scythian groups of paleo-Iranian origin, gradually evolved into the ancestors of all modern Germanic and Celtic Western ethnicity. Saka/Sakya is merely another word Scythe, Scythia, Scythian, Cimmerian (etc.)–the Pali canon describes the Buddha as blue-eyed and moon-like of aspect. The founder of Jainism was likewise an Indo-Aryan Kshatriya opposed to sacerdotal ritualism. I am not being “racist”, these are simply relevant facts.
The *Dhamma * (Pali) is essentially a form of metaphysics transcending the dichotomy of “religion” and “philosophy” the Western tradition has developed as a form of intellectual corrosion. I honestly apologize in failing to know English verbiage befitting Buddhist metaphysics. The non-linearity of the subject constrains my intellect.
What I can further state: the original Pali canon is the authentic Buddhist “ontological metaphysical philosophy.” Extraneous developments of later history, e.g., so-called “Vajrayana” Tantra , etc., represent nothing but mutilation and manipulative appropriation of authentic Buddhism.
Foul Tantra of Vajrayana took the subtle Madhyamika doctrine, and vulgarized its meaning, as to imply, the absolute identity of samsara and nirvana, resulting in antinomian moral iconoclasm and subversive moral nihilism, Indo-Tibetan primeval demonology and degenerate Shaktism of pre-Aryan, pre-Vedic matriarchal phallic worship, re-asserting itself and usurping all: here is where Buddhism died, the Mahayana ideology of “liberalism” critically self-dissolved, and another creature appeared…its lowest form, vamachara, lit., “Left-Hand Path” heterodoxy (an arrow of Satan in the West today, in the form of Crowley’s irregular O.T.O., etc., diverse resurgent expressions of Gnostic Libertine Satanist madness)…Buddhist Tantra is comparable to the heresies of Gnostic-Libertine character mutilating incipient Christianity, such as the Sethian, Carpocratian, Ophite, etc. cults of perversion. Tantra is morally sickly, a form of moral inversion having nothing to do with original Aryan Buddhism. I hope we can keep this in mind.
Please excuse me for my failure to answer your question. Your question is very heavy, Sir.