Final Fantasy XV was intended to have a second season of DLC story episodes, but they were all canceled (save for Episode Ardyn, which was already in development) and the director of the game left Square Enix. The remaining canceled story episodes were going to focus on Aranea, Lunafreya, and Noctis.
The story of the cut DLC was promised to be featured in a novel called Final Fantasy XV - The Dawn of the Future, which is now available in Japan. One of the special editions of Final Fantasy - The Dawn of the Future comes with an art booklet that features concept art from the canceled DLC story episodes.
Concept art from the canceled DLC episodes of Final Fantasy XV has been uploaded to Twitter by @FFplanet, which has revealed that an entirely new scenario was planned that would retcon several aspects of the game.
Few pieces of concept art from FFXV -The Dawn of Future- Artbook— BoN (@FFplanet) April 26, 2019
1. Luna from Episode Luna. The Draconian recovered her body with power of daemon and revived her to fulfill the new mission. She has the power of daemon like Ardyn. pic.twitter.com/f1qiNwnaXK
Lunafreya dies during the events of Final Fantasy XV, but she was going to be resurrected by Bahamut and given the same demonic powers as Ardyn. Episode Noctis would have involved a final battle against Bahamut, that would have involved a team-up between Aranea, Ardyn, Lunafreya, and Noctis.
Bahamut would have been defeated and Lunafreya truly brought back to life, but Ardyn would perish in the process and a state funeral would be held for him. The new ending of the game would show Noctis and Lunafreya with their two children.
Final Fantasy XV had a bittersweet ending, with both Lunafreya and Noctis sacrificing themselves to save the world. The Episode Ignis DLC offered a non-canon ending where Ignis was somehow able to save the world without any sacrifices (possibly with the help of coming up with new recipes), so it has been obvious for a while that there was a desire within the development team of Final Fantasy XV to offer a happier ending.
It's a shame that the second set of DLC episodes for Final Fantasy XV was canceled, as the public will never get to see these cut stories played out, except in literary form. Final Fantasy XV had one of the most troubled developments in the history of the series and it's a shame that the whole story will never be realized.
Final Fantasy XV - The Dawn of the Future will be localized outside of Japan, but no release date has been given.