The Sou(ou)Shi are15 foot tall, with huge serrated jaws, four arms ending in triple scimitar blades and legs like iron pistons.
When they are going to kill, they project a psychic image of a larger version of themselves, with snouts, tusks and razor-sharp claws. They are also known to project a human-like image of themselves, but too pink, with eyes too round and fine golden fur on their torsos.
They are a group mind. They consume the mind energy of dying species without space travel and use their bodies to start life on habitable but uninhabited worlds, where new life develops based on that species' genetic code. This is how they "save" doomed species. In effect, they are psionic vampires..Previous races they have devoured include the Philotirians, the Aveletians, the Signortiyu, and the Gowenn. One of these races was humanoid, but dwarf-sized with three eyes.. They have considerable psychic abilities - including psi-probes and psi-weapons. They have neural amplification fields, which use someone's nervous system to put them in severe pain.
They are incapable of lying, and so hide their true intentions from their victims by telling them only part of the truth. They cannot kill without the permission of their victims. The Sou(ou)shi keep examples of the art of cultures they devour.
Some 3 billions years ago, they had developped a space faring civilisation with ships that had perfect gravitational control caused no atmospheric displacement. They became extinct around that time.