what was marked as the beginning of obi's downfall

Corruption seems to be rife within the senior service, and, indeed, within the colonial bureaucracy as a whole. It is commonly assumed that bribery is something everyone does, both in white and black circles. There are several attempts to bribe Obi before he actually accepts it. I think that accepting the bribe begins his downfall.

Contrary to common opinion, I would actually say that Obi's downfall started from the moment he followed the path of his colonial authorities, refusing to match it with the morals of his own culture. For example, Obi had chosen to marry Clara, even though it was against his culture, impregnated her before marriage, and left her in the hands of a doctor willing to carry out illicit activities. Obi, in his pursuit of the Western world, lost his morale centre.