I cannot take credit for creating these creatures. The existed in the fictional world long before I came around. According to popular definitions (courtesy of Wikipedia) a cambion is the offspring of an incubus or succubus or demon of any kind (yes, incubi and succubi are demons, not sure why the distinction is made), and a human. Merlin, yeah the wizard from King Arthur, is a well known cambion, as is Hellboy. In season 4 or 5, the CW show Supernatural featured an episode with a cambion. Players of D&D are probably familiar with the term.
How do Cambions exist within The Cambion Rider Chronicles universe:
Cambions are half-demon / half-human or in very rare cases... half-demon / half-dragon rider. Due to the sterility of demons, they need to employ the use of an incubus and succubus to secure an offspring with a human. It is not an easy process which leads to there not being a great number of cambion in the world. Most cambions are born from human mothers. (read After the Flesh for more!)
Cambion are neither innately good nor evil, however, their nature makes them more susceptible to corruption and demonic influence than the average human. Some believe cambions have a predisposition to embrace their paternal lineage and become full demons. It is also a popular belief that if a cambion learns their true nature and do not succumb to their demon bloodline they will go insane. There are no documented cases so this may or may not be fact.
Because of their demonic pedigree, cambions are generally despised by dragons and riders alike. Due to being half human they refrained from outright killing them, however, once a cambion was discovered, dragons and/or riders tagged and tracked them through the rest of their lives, killing them instantly if they went full demon, and potentially tagging and tracking their offspring.
Some cambions display some form of precognition or clairvoyance. The strain this places on the psyche is believed to contribute to the descent into madness. It is believed when the abilities grow stronger, this is a prerequisite to the fall into the demonic or madness.
And that's cambions. Feel free to leave any questions in the comments below, especially if this raised more than it answered.