The Ura Files

Average high school student Momotaro Kibitsu is actually a secret agent entrusted to protect the nation! His mission is to surveil Ura, a beautiful classmate who happens to be the descendent of oni! He's trying not to let her charm him, but the more he gets to know her... From the creators of Super Psychic Policeman Chojo and Teenage Renaissance! David comes the ultimate rom-com school adventure!

(Source: MANGA Plus)