Final answer:
Njoya's pipe is likely associated with culturally detailed entities like the Bamum culture or the Grassland Kingdoms, which are linked to the history and craftsmanship of royal artifacts in the Cameroonian region.
Step-by-step explanation:
The title of the pipe belonging to Njoya is not explicitly provided in the reference information you have, but considering the cultural context and artifacts mentioned, it seems most likely that Njoya's pipe would be associated with the Bamum culture or the Grassland Kingdoms. These regions and their cultural artifacts, such as terracotta and brass pieces, are connected to the kings and royalty of those times in the Cameroonian region.
Furthermore, the widespread African culture associated with crafting such items often correlates with royal or high-status individuals within kingdoms, suggesting that Njoya's pipe, as a possession of significance, would typically fall under culturally detailed categories like Bamum or Grassland Kingdoms rather than general categories like Cameroon or materials like terracotta and brass.