Lost Queen : Ah, Benach’Seir~
Yes, that is true for the most part. It is us that hones our powers with the magics of evil and darkness.
But a roster? Oh spirits, I do not know if I could list all the elementals. As there can be so many deviants under the same elements. Some fire elementals could not breathe fire, but could manipulate fire, only breathe gusts of heated smoke, shoot heated coals, or even streams of scalding water. Some wind elementals could only deal with sandstorms and others lightning. Most dragons were unique in their powers, and trained under one or possibly even multiple schools to master their abilities.
There were colleges and schools Kuros could go to, such as a fire elemental school, magic school, water schools, etc. I personally went to a Magic college but majored in Aura Magics, minoring in Dark Magic (using blood magic and darkness spells) before going into Military/Queens colleges. In order to apply to upper colleges at all, you had to have a masters (or doctorate in some fields) in your element. Convexity was eventually labeled as Dark magic, like my major it was considered a form of Aura Magic, where one uses their own aura or spirit energy to form attacks.
All Kuros were able to use magic in some form, even if they do not know it. It can take years to tap into those magics if they are not raised with it. It is our connection with the darkness that gives us this natural ability. We just use this magic to aide us in honing our abilities for evil purposes. There are Kuros that use dark magic alone as their ability, and they are the most dangerous magicians in Skylands. Or, were, rather..
