Classroom for Heroes, Vol. 3 (novel)

Blade, now surrounded by his 111 friends (including two birds and a dragon), should be enjoying his sweet school life…So why isn't he?! Well, first his class is invaded by a superstrong guardian out to defeat him, then he's forced to challenge the king to a duel with Earnest as collateral! And as if that wasn't enough, the students of Rosewood Academy must face more of the king's so-called "practical training," brave mixed-gender hot springs, and survive a trip into the bowels of the royal castle. This ex-hero may be retired, but his adventures aren't over yet!