War Sphinxes were midsize Forerunner fighting suits used during the time of the Human-Forerunner wars. They were powerful war machines that were generally dropped from high orbit, and were capable of sweeping continents and decimating entire cities.
The Ur-Didact's twelve war sphinxes were left on Erde-Tyrene to guard his Cryptum. By the time Bornstellar-Makes-Eternal-Lasting visited the planet in approximately 100,000 BCE, the suits were considered antiquated and outdated.
The War Sphinxes were described as being ten meters high and twenty long, with an elongated tail that provided lift and power. From the "tail" rose a large rounded torso with a command cabin perched on top. The command cabin was designed to resemble a Forerunner face, with features arranged in an angry or stern expression and two viewports serving as "eyes".
War sphinxes were programmed to contain samples of their wearer's mental patterns and personalities before they are killed in battle. These preserved personalities were less realistic or complete than Durances, but could still be studied by a commander to gain useful information. The Didact kept the final impressions of his children, who were killed in battle, within their war sphinxes.
- In one of the Terminals, a recommendation of Forerunner armor by Mendicant Bias is accompanied by a mysterious image. This image depicts a bulky, rounded object with what appears to be a long tail and a humanoid figure inside. This seems to match Halo: Cryptum's description of a war sphinx. It could also be an image of the war sphinx's newer counterpart, a Seeker.
- It is possible that the War Sphinx is the Forerunner equivalent to the UNSC Cyclops or Mantis.
- Due to its role as a combat exoskeleton, the War Sphinx may be classified as a high-level Combat Skin.