Short answers, pulled from the story.
Crystal Tools is a game engine created and used internally by Square Enix, the Japanese video game developer and publisher. It combines standard libraries for graphics rendering, physics processing, motion control, cinematics, sound, artificial intelligence, and networking, and also provides various authoring tools for large-scale game development.
Crystal Tools targets the PlayStation 3, Xbox 360, Microsoft Windows, and the Wii. Support was extended beyond the PlayStation 3 to reach Western markets where the Xbox 360 and Windows were successful, though the Wii received only preliminary support and never ran all components of the engine.
Development began in August 2005 under the code name White Engine. It was led by Taku Murata, who served as general manager of the Research and Development Division, which was established specifically to build the engine.
Crystal Tools caused significant delays because the team tried to accommodate demands from multiple game projects simultaneously, which prevented the engine's specifications from being finalized. Assets created by the Final Fantasy XIII team during development turned out to be incompatible with the unfinished engine, compounding the problems. Producer Yoshinori Kitase later said building an engine from scratch alongside a new game may have been a mistake.
Five games were released using Crystal Tools: Final Fantasy XIII in 2009, Final Fantasy XIV in 2010, Final Fantasy XIII-2 in 2011, Dragon Quest X in 2012, and Lightning Returns: Final Fantasy XIII in 2013.
The name Crystal Tools was adopted after version 1.0 was completed in September 2007 to better represent Square Enix and its works. The refractive properties of real-life crystals were chosen to symbolize the flexibility of the engine.