Short answers, pulled from the story.
The story follows Cecil and Rosa seventeen years after the original events as they face threats alongside their children Ceodore and new allies. The narrative unfolds through monthly chapters released to mobile phones before converging into a unified finale where Golbez emerges as the Man in Black.
The Japanese mobile version launched under the title Final Fantasy IV: The After Years in 2008 before transitioning internationally. One million downloads occurred within five months following initial release in August 2008 excluding free prologue chapters.
Takashi Tokita served as producer when Square Enix approached him about creating a mobile sequel during 2007 development of the Nintendo DS remake. Matrix Software handled co-development while preserving 2D sprites to evoke nostalgia for the original title with Kazuko Shibuya returning as 2D sprite artist.
Square Enix introduced the Age of the Moon system in 2008 to alter battle dynamics based on lunar phases that shift at each inn rest or passage of time. Each phase changes physical and magical attack powers for both player characters and enemies while certain rare monsters appear only during specific lunar phases.
WiiWare ports appeared worldwide in 2009 featuring larger screen resolution and clearer menu screens compared to the original mobile release. iOS and Android platforms received a 3D remake released the 24th of November 2013 using the same visual style as the Nintendo DS version before Steam brought the Windows port to global audiences on the 12th of May 2015.