After these events, Irene successfully integrated into the Fairy Tail guild. Natsu and the others also learned that Irene was a new teacher specializing in teaching Dragon Slayer Magic, though this wasn't of much use to Natsu anymore.
Because he had already applied for the graduation exam.
Gajeel, Gray, and Lyon had also applied for the graduation exam. Rogue and Sting wanted to apply as well, but based on their rankings in the previous preliminaries, Alan flatly rejected their application, approving only Natsu and the other three.
Chapter 179