Because Koffi decided to leave late Jean Louis Manzugidi behind in Kinshasa and Beevans Rappa hadn’t reached the maturity to animate alone yet and hadn’t enough staminaAccording to Beevans himself when he just joined he had a lot difficulties with animating and Willy Bula helping him often out. I believe that Koffi saw that he could use him in the place of him, since that he wasn’t happy with Manzungidi anymore.There used to a video of INA Congo on YouTube, where you could see comedian Ngadiadia doing advertisements for his show and toward the end of the video you could see Koffi, Fifi, Do Akongo and co promoting their show and on the moment that Fifi was dancing, you could hear Wily Bula doing animation