The Maelstrom Mod introduces four new races to the Sins of a Solar Empire Rebellion Universe. They are independent of the original races and have unique strengths and weaknesses. Maelstrom is available for Rebellion, Diplomacy, Entrenchment and Original Sins.
Quoting Elite222 ...
"The Advent, TEC, and Normis have launched their offensive. Now we get to press the Trade Alliance's economic power house to its limits in this installement of Maelstrom on Maelstrom XD"