Esper is a world where purpose and control have triumphed over savagery and chaos. Bereft of red and green mana, this plane's natural forces pale next to the supernatural power of its human and vedalken mages. Under the foresight of Esper's ruling sphinxes, the plane has transformed from wilderness to a tightly-controlled magocracy, with all forms of life perfected through the æther-infused metal known as etherium. Travelers to Esper should expect a spectacle of sophisticated beauty, where not only the plane but also its denizens have been meticulously designed according to a grand plan.
Esper has clouds that are dissected and skies that are marked and measured by flowing lines of mystical dust. It has vast dark oceans and deserts of fine sand that are cast into the firmament by prevailing winds. It has elaborate, stylized towers with curved flowing shapes that show craftsmanship and control over the elements. In the lower depths of these highly crafted tower cities is the eternal gloom of the tidehollow, a dank underworld inhabited by unwholesome creatures.
In this world of wind and wave, control is the guiding force. Cut off from the chaos of red and green mana, Esper has become a magocracy. Enigmatic sphinxes counsel powerful wizards and seers. Everything here is observed and controlled. The forces of high magic rule supreme.
Over time, all of the creatures of Esper have changed themselves over time, upgrading themselves by incorporating Etherium metal into themselves. Some have only touches of filigree, but others have enough to create elaborate filigree appendages, a hallmark of high rank in Esper. As a result, they are functionally magical cyborgs, and share many traits with constructs.
It's the goal of the council of mages known as the Ethersworn to infuse every living thing on Esper with etherium. That implies that there are some organisms that have no etherium—but still, their success rate is pretty high. Almost every single being on the plane has etherium filigree - the Ethersworn miss little. The process takes time to work on creatures that may have just appeared in the plane, and might miss some creatures that are too small or delicate to support invasion by etherium.