Long ago, humanoids discovered that tampering with the chemical composition of certain glasses and metals can change their structure. Since these peoples began to explore the expanse of space, it has been documented that, in rare cases, certain humanoids may have their genetic compositions altered in a similar manner: These folk become known as Tempered. Just as in the tempering of glass, beings who experience this change have their composition stressed to near breaking point. When this stress is released they revert to something close to their original form, yet only in appearance. Not all survive the transformation, but those who do are bestowed either a gift, or a curse depending on one's perspective. Most do not remember their transformation, but those who do recant a pain which cannot be adequately described. 

The Tempering of a creature can only occur when its genetic makeup is compromised by a cosmic anomaly. Mutations accompanying these changes can often provide supernatural powers, yet this comes at a cost. Their physical features or senses are often marred or altered. Never allowing them to, fully, return to who they were before. Though it is unclear why, any who have cybernetic alterations are immune to these changes, yet are not to any other effects of the many cosmic anomalies in the universe.