SO PLEASE DON’T READ ON IF YOU DON’T WANT SPOILERS…
The four friends undertake a journey to find him a bride, at the behest of Gentianas.
Noctis Lucis Caelum is a quiet, bookish boy with a penchant for sleeping and still grieves the death of his father. To cope, Noctis spends much time with his friends: Gladiolus Amicitia, whose family are criminals and alcoholics; Ignis Scientia, an eccentric and physically scarred boy; and Prompto Argentum, who is severely underweight and timid, often making him the target of Gladiolus’ bullying. They want to search for Stella Luna Lunafreyamarche Nox Jingleheimer Schmidt Fleuret so that Noctis and her can marry to reclaim the thrones in their respective kingdoms. So Noctis, Gladiolus, Ignis, and Prompto decide to follow the highway and find her. Prompto steals his father’s M1911 pistol; he, Noctis, Gladiolus, and Ignis head out in the Regalia.
boys men stop at a nearby mechanic shop to get a drink. The head mechanic is notorious for being the owner of a vicious and rarely seen behemoth, Deadeye.
They hang out in the mechanic shop for a while. The boys send Noctis out to buy food at a nearby general store. When Noctis returns, he sees the others jumping the fence. Noctis walks over to join them; but Cindy, the head mechanic, spots him and sends Deadeye after him. Noctis runs and jumps the fence with Deadeye in close pursuit, barely escaping. They discover that Deadeye is a small baby behemoth who wouldn’t hurt a child. They tease Deadeye, but Cindy arrives and calls Ignis’s father a “loony”. This incites Ignis’s uncontrollable rage, causing the others to keep him from attacking her. Prompto, Gladiolus, and Noctis help him forget by playing Justice Monster V on a pinball machine.
While at camp, Prompto tells the others a story of his life. He was born with a glandular condition which caused him to become obese. Because of this the other kids and family members ridiculing and teasing him. Prompto enters a pie-eating contest; but his main goal was not to win, but to exact revenge. Prior to the contest, he consumed Malboro oil and raw chocobo eggs, working as emetics. After eating a fifth cup of Ramen, he projectile vomits, inducing the vomiting of all the crowd.
Everyone but Gladio liked the story.
TL;DR: After a series of misadventures and much self-revelation within the gameplay, they locate Lunafreya.
However, Verstael and Aranea Highwind arrive to claim her first. When Gladiolus refuses to step aside, Highwind pulls out her switchblade with the intent to “lightly slash” him. Noctis intervenes and threatens to shoot Verstael with Prompto’s unloaded M1911 pistol. Clearly outmatched, Verstael and Highwind simply shrug and walk away. That’s it. This is the final battle.
No other villain exists.
Noctis and Gladiolus stayed friends; they drifted apart from the other two shortly thereafter. Prompto married, has four children, gained weight and drives a forklift at a local lumber yard. Ignis enlisted in the army despite his impaired eyesight. He had served some time in prison and now does odd jobs. Gladiolus went on to college and became a lawyer. When attempting to break up a fight in a diner, Gilgamesh lightly slashed Gladio down his chest.
The game ends with Noctis marrying Lunafreya. His son asks him again if he is going to take him swimming. Noctis goes outside of his opulent kingdom, driving away with Luna in his Audi R8.