David Mogo, Godhunter by Suyi Davies Okungbowa

The heavens have burst and the gods have fallen. Some are minor pests, mere godlings, but some are high gods with unknown magics and powers. David Mogo, a half-god, contracts himself out to the people of Lagos to help with godling infestations. However, when the local ruling wizard offers him a contract to capture a pair of twin gods, David knows the job is bad news.