The game ends with a final battle against Llednar which is a kind of an alter-ego of Mewt’s desire to stay in Ivalice, after the battle, there’s a long speech about responsability and how you need to face your everyday problems, they all go back together, then the game ends with Mewt standing up for himself in cthe playground, and the sort.
If you try to go for the 100% completion, you’ll have to do a small arc of quests against the judges with Mewt’s father on your party, after you win Marche gets a Judge sword.
thats probably in the second game