@Khansolo
They realize that the forest is made by the plant magic teacher.
They try to use the spell they learned on their first day of plant magic class.
They need mana to activate the plant.
Reid is out of Mana.
Iruma (or rather the spirit trapped in the Ring of Devouring) is out of mana.
Clara who's been unknowingly absorbing everyone's and everything's mana thanks to her succubus lessons is full of mana (Iruma was unaffected by her drain powers but the ring was drained)
They use Clara's mana to activate the plant.
Plant activates Iruma has a vison of the Lost Demon king Derkila (say his name out loud), the one that Sarbok is always going on about - chapter 93 was when we saw the most of him last.
Harvest festival ends.