As the title suggests, this newly-emerged fan project is a mod for Ultima 4 that will function very much like an expansion pack for the game: it will add new content, new quests, and new locations and features, but will not impact the base game, its story, or its quests in the process (although a few bugs present in the original Ultima 4 may end up being squashed along the way).

In particular, Cambragol’s Advent of the Trinity will add new hamlets and towers, new dungeons, new artifacts, new shops, second levels for all towns (and for castles!), diagonal attacks and variable battle maps, an Ultima 5-like reagent system, Virtue-based NPC reactions, and more. Original Ultima 4 save files will continue to work with the game after the mod is installed, as well.

An alpha demo — playable online! — is currently available. You can also follow the mod’s development blog, though at present there are not many updates posted thereto. There is also a freshly-created project entry for Advent of the Trinity here at the Codex.