Shonen onmyoji (2006)

Abe no Masahiro is the grandson of the greatest Onmyouji Abe no Seimei. His grandfather sealed his sixth sense (the ability to sense monsters) in order to protect him. He doesn't know about it until he meets Mokkun. While fighting his first monster he breaks the seal and his quest to become the next greatest Onmyouji begins.