The beliefs and practices of the religions in Borneo exhibit wide variation, but there are features which are commonly characteristic to all. Though the indigenous peoples all speak Austronesian languages, there is complex ethnic diversity which is reflected in the religions since the religions are rooted in the local communities and contribute to much of their identity. Religion in fact is integral to the way of life in Borneo, without there being the concept of a separate domain of religion.
Ritual observance is an essential part of life in marriage, etiquette, law, and other aspects.
Each religion has its own ritual forms and there is no such thing as conversion from one religion to another. If an individual moves to live in another community through marriage or some other reason, then they follow the ritual of that place. In the interior the religions are rich in ritual and cosmology. The Ngaju have doctrines of an upper world and an underworld together with multi-layered heavens. Such doctrines of extensive spirit worlds are found with other peoples in Borneo.