This is not the first event crossing over Terra Battle and a Final Fantasy game, as a Mobius Final Fantasy event just went live today.
Terra Battle is currently available for iOS and Android, while Final Fantasy XV is available for PS4 and Xbox One.
Looks like the rift between Final Fantasy Creator Hironobu Sakaguchi and Square Enix is pretty much healed, as his studio Mistwalker announced a brand new crossover event between its mobile RPG Terra Battle and Final Fantasy XV.
He was also present at the Uncovered: Final Fantasy XV event, and sent a hilarious video message during the Final Fantasy 30th Anniversary Celebration event.