Black Sun, Silver Moon

Taki thought he knew exactly what he was getting into when he accepted a job at the church as an assistant -- but the job description never mentioned dealing with zombies! When night falls, the mysterious priest Shikimi and his new assistant venture into the graveyard to destroy the freshly risen dead. The enigmatic priest always seems to know when and where these creatures will appear, and as the days go by, Taki begins to suspect that the danger may also come from within...

source: mangaupdates