beta
Hear me out first!
What happened is that he is working with Sabnock's uncle to "restructure the demon world." Remember that the border patrol captain (?) is Callegos sensei's brother who approved the other two to show up at school and check on Iruma (since he became a candidate) and when Callego sensei went to talk to him at the party he basically confessed. Also, he helped Sabnock's uncle at the party to get on the princess good side so they could manipulate her into approving what they wanted.
So it makes sense that he wants to destroy his crops, his test, and the hopes of the many ears for "stepping above their status" and unmaking their new world order they want to create.