Busted! Darklord.

Following the disastrous military defeat of the Demonic Sect, demonic factions are driven to the brink of extinction by righteous orthodox martial alliances. In a desperate bid for political survival, Yu Renjie, the pampered young son of the fallen Demon Lord, is ordered to infiltrate the prestigious Hero Academy. To preserve his clan, Renjie must disguise his wicked demonic heritage, pass rigorous moral examinations, and secure an official Righteous Hero Certificate. Terrified of exposing his demonic identity to fanatic instructors and righteous peers, Renjie relies on absurd excuses and quick wits, ironically becoming the academy's top hero.