The Teen Exorcist, Vol. 1 (manga)

Japan’s Heian Period. Masahiro serves as a royal diviner just like his grandfather, the legendary Abe no Seimei. His dream isn’t to follow in his grandfather’s footsteps, though—it's to surpass him! During some intense training with his spirit companion, Mokkun, Masahiro notices an ominous presence targeting the princess...Can he protect the royal capital and escape from his grandfather’s shadow?!