The religion of the Mangbetu is reflected in their material culture. The material wealth of "great rulers" included many items that were reserved for their exclusive use and that symbolized their links with divine authority. For example, the skin, tails, teeth, and claws of leopards were sacred and were reserved for the use of the king alone; the nekire (whistle) and bangbwa (war drum) were used exclusively by the king to protect his people or goods or to bring good luck. The king was also believed to have the ability to control rain, which he used not to help with the crops but to permit outdoor gatherings and to serve as a weapon in war.
In the nineteenth century another supernatural force entered into Mangbetu society, possibly in the context of a secret society that was focused on Mangbetu opposition to colonialism, but perhaps even earlier, in the 1850s. In the beginning, this force, called nebeli, seems to have been a potion that could attract animals to traps and subdue feared animals. Later, it was used to defeat enemies. Eventually, its use was incorporated into the rituals of a secret society, also known as nebeli, the purpose of which was to protect the larger community and its culture. Most Mangbetu leaders of the twentieth century were nebeli members, and most used the society to strengthen their rule over their subjects.
Belgian colonialism, beginning early in the twentieth century, drasticallly changed Mangbetu society. Generally speaking, there was acceptance of Belgian rule without full Mangbetu cooperation or participation in the Belgian administrative system. The Mangbetu and their subjects accepted Christianity very slowly and sent few of their children to European schools. Mangbetu production of cash crops was lower and more painfully extracted than elsewhere in the Belgian colony. When towns grew up around administrative and commercial centers, the Mangbetu participated in relatively small numbers. By contrast, other groups, especially the Budu, became clerks, servants, drivers, laborers, vendors, and students.
A prevailing explanation for Budu successes (and Mangbetu failures) is that the Budu were under attack from the Mangbetu at the time of colonial contact, and so conformed to European wishes in order to save themselves. Conversely, the Mangbetu, who were proud conquerors, withdrew in defiance and preferred to reminisce about past glories and plot a return to power. It is clear that Mangbetu prestige suffered with their loss of slaves, the end of raiding, the disgrace of being conquered, and other such humiliations, but colonial policies also kept the Mangbetu from developing more successfully. By prohibiting the entrepreneurial activity of lineages, by reducing the prestige of the Mangbetu court, by regulating succession, and by reinforcing the power of the "great rulers" to keep subjects in line, the colonizers effectively suppressed Mangbetu culture.