Tensei shita Wakiyaku Heibon na Boku wa, Bike Dai Ni Ouji Wo Yandere ni Shite Shimatta

Emil, reincarnated as a mob servant in the otome game “Renancia Story.” This game is insanely difficult—if his master, Prince Albert, doesn't achieve a happy ending with the heroine, the Holy Maiden Maria, they both face a dead end! To survive, he must somehow get them together— Emil strives to make Albert and Maria fall in love, but Albert shows absolutely no interest in Maria. Instead, for some reason, he becomes fixated on Emil...?

(Source: AlphaPolis, translated)