Kyuuketsuki to Chocolatier: Tensai Renkinjutsushi no Kanbi na Tankyuu @comic

Luvilia, a mysterious city where the supernatural gather. Poor alchemist Alfred is risking his life to challenge is... making the "ultimate chocolate" to offer to the vampire Shin!? The key to breaking the forced master-servant contract is a "blissful sense of being alive." That is his only weakness. Will Alfred kill him first with a single, supremely sweet morsel, or will he become his servant first...? Where will this sweet, melting battle lead? "Even your murderous face is enticing, isn't it?" "Drop dead already, you shitty vampire!" An absolute master-servant Gothic sweets fantasy!

(Source: TO Books, translated)