Short answers, pulled from the story.
Dissidia Final Fantasy Opera Omnia is a free-to-play mobile role-playing game set in the Dissidia Final Fantasy universe, developed by Square Enix and Team Ninja for iOS and Android. It features turn-based battles and characters drawn from across the Final Fantasy franchise.
Opera Omnia launched in Japan on the 1st of February 2017, and worldwide on the 30th of January 2018. The game concluded service on the 29th of February 2024 on all platforms.
Opera Omnia launched with 25 playable characters and expanded continuously through updates. By the end of service, the Japanese version had 179 characters and the Global version had 175.
In June 2022, Square Enix announced that Dissidia Final Fantasy Opera Omnia had surpassed 10 million downloads worldwide.
Opera Omnia was co-developed by Square Enix and Team Ninja, the same studio that developed Dissidia Final Fantasy NT. Square Enix published the game as the owner of the Final Fantasy franchise.
A user named Hatok recorded all cutscenes and battle sequences from Opera Omnia's storyline before the 29th of February 2024 shutdown. The project produced approximately 100 hours of footage, required more than 2 terabytes of storage, and was completed seven hours before the servers closed.