A coalition of species who attack Earth in 2153.
The Xindi are a coalition of several species from the Delphic Expanse, including humanoids, reptilians, insectoids, arboreals and aquatics. They once shared a world, Xindus, which was destroyed, and the survivors went on to create different societies. The Xindi council once represented them all.
In Enterprise, the Xindi are manipulated by beings called the Sphere Builders, who convince them that humanity will destroy them in the future. The Xindi build a weapon in order to destroy Earth, and test it first on a part of the planet. Their culture is shown as split, with a variety of opinions about the way to proceed.
The Xindi storyline runs through the third season of Enterprise, in which Captain Archer and his crew journey into the Delphic Expanse to stop the weapon. Dr Degra, a Xindi scientist, comes to doubt the attack, and Archer persuades him to help. The crew eventually discovers the deception and convinces the Xindi to join in the defence of Earth, which marks a turning point in the early years of the Federation.