From Might and Magic wiki:
Might and Magic: Swords of Xeen is a free, downloadable fan-made modification of the World of Xeen engine developed by Catware, designed and directed by Bill Fawcett and released in 1995. As the earliest full-scale Might and Magic project made by fans of the series, it was also the first installment in the series to be developed by a company other than New World Computing.
Subsequent to its final release, Swords of Xeen was authorised and published by New World Computing and The 3DO Company in the form of a bonus scenario, distributed with anthologies of the early Might and Magic RPGs. It was first included in the Might and Magic Trilogy compilation, and has most recently been made available in the Might and Magic 6-Pack from Good Old Games.
Swords of Xeen follows the events of Might and Magic V: Darkside of Xeen, and focuses on a party of six adventurers, the last able servants of the dragon pharaoh. Commanded to investigate an enigmatic portal in the city of Greyhaven, they are teleported to Havec - a dystopic and deeply corrupted wasteland-like world - where they discover, and strive to destroy, the malign force which orchestrated the actions of Sheltem the Dark and Lord Xeen.