Seikishi desu ga, Takane no San Seijo no Dareka wo Yotta Ikioi de Daiteshimatta Ken ni Tsuite

Blade endures harsh training alongside rivals and three elite saint candidates to become his dream role: a Holy Knight. But one absolute rule governs these knights: they must only bond with a partner officially recognized by the Church. Violating this means ability confiscation and expulsion. One morning, Blade awakens to find a Sacred Mark—proof of an unrecognized bond—carved onto his lower torso. Now he must find his secret partner while guarding the mark's existence... or face ruin!