Quote Originally Posted by masamune1600
Calling Final Fantasy: Legend of the Crystals a sequel to FFV is somewhat deceptive. While it did follow the events of FFV, and was relatively loyal to the game, it wasn't produced by Hironobu Sakaguchi or anyone else officially associated with Final Fantasy. It's not actually a game, by the way, but rather an anime split into four chapters: Fire, Wind, Dragon, and Star. The cover specifically says "based on", so while it is a sequel, it's not an official sequel, per se. Or, at least not in the sense that FFX-2 and the different parts of the Compilation of FFVII are sequels.

Some information on FF: LotC can be found here. Just enter the segment designated "LotC."
While not developed by the folks at Square itself, it was produced with their permission and under their supervision. "Square Co. Ltd." is in the credits under "Production Cooperation," and Hironobu Sakaguchi and Nobuo Uematsu are under "Production Supervision."

It's still a sequel in that it's based off of plot elements of Final Fantasy V specifically, and it's really still official in that Square gave their permission for the project to be made, supervised it, and had the power to prevent it from being made if they had so wished.