At first the Shén were neutral to man, but they soon determined that if they remained passive, the aggressive human worlds would expand and envelop their region and stiffly resisted human attempts to push them off. A series of small engagements resulted, and both sides suffered losses.
Eventually men and Shén came to realise that this was a fruitless enterprise—the logistics of interstellar war are too difficult to make it profitable—and the Treaty of T’kru (the Shén world capital) was signed. Trade developed, and mutual respect also came into being. Although ferocious in battle, the Shén had never been needlessly cruel—and fortunately at this time in human history the forces fighting the Shén were followers of the Transporters, a highly moralistic, authoritarian, almost prudish sect. Neither side thus committed atrocities, and peace came easily once war was done.
Transporters? It seems likely that the Transporters were a human faction or pocket empire in the Beyond at the fringes of Shén space. Why were they known as the Transporters? Perhaps they were attempting to transport something or someone (themselves, a substance, an entity, a star, an ancient device?) through the Shén Star Empire toward the Galactic Core. Or...were they known as the Transporters because they had the power to transport? Or....