The Hero and the Love Barrier

The hero continues his journey to defeat the Demon King... Just as he's about to reach the Demon King's castle, he receives news that the academy where he once studied is under attack by monsters! The protagonist rushes to aid the academy! After successfully saving the academy, he investigates the cause of the monster outbreak... While trying to eliminate the cause, he's suddenly ambushed and loses consciousness... The last thing the protagonist sees is the figure of Mill, a junior student who was very close to him and always looked up to him...