D'arc Hoshino is the partner of Tensai Ikkyū. D'arc is a teenager of average height who has dark skin and partially tied-back umber hair with golden eyes. D'arc is usually shown wearing the Nanae Island Third High School girls' uniform, the rest of the time in a maid costume. D'arc is never seen wearing male clothes. On page 150-152 of "Tensai's Reluctant Deduction" an illusion of genderbent D'arc and Tensai are shown. D'arc is primarily shy and optimistic. In contrast to Tensai, who is loud and brash, he is quiet and kinder to people. He seems to have an attraction towards Tensai Ikkyū, which has not been completely proven, but is strongly implied. D'arc has always been seen fawning over her. He appears to be a bit of a crybaby at times.