Short answers, pulled from the story.
Dissidia Final Fantasy NT is a fighting game with action role-playing elements developed by Team Ninja and published by Square Enix. It is available on PlayStation 4 and Windows, and is a console port of a 2015 Japanese arcade game.
Dissidia Final Fantasy NT released on PlayStation 4 on the 30th of January 2018. A free-to-play version called Dissidia Final Fantasy NT Free Edition launched on the 12th of March 2019 for both PlayStation 4 and Windows via Steam.
Dissidia Final Fantasy NT features 38 playable fighters in total. The base roster at the PlayStation 4 launch included 28 characters, with ten more added as DLC after a period of arcade exclusivity.
The NT in the title was confirmed to have multiple meanings: New Trial, New Tournament, and New Tale.
Dissidia Final Fantasy NT sold 105,667 copies in its first week in Japan, making it the best-selling game of that week. It reached 134,100 units sold in Japan by the end of January 2018, though Square Enix later reported that overall sales fell below expectations.
The scenario was written by Kazushige Nojima, who also served as supervisor, based on a draft by Saori Itamuro. Itamuro had previously contributed to the original Dissidia and to Final Fantasy XV.