History
Waves themselves actually come from the Sage Dimension. While most sages come from mythical beasts that chose human form Waves are considerably different.
Each and every sound runs through soundwaves in the air; They are then picked up by your ear and processed by the brain. Waves evolved from the soundwaves created by Sages in the Sage Dimension. They congealed in one place and combined with residual magic in the air and became sentient.
They now had a survival instinct.
Slowly but surely they observed Sages and their creation into human form, they saw that while their lives were fleeting and short without constantly resounding from one another those of a Sage were long; Almost constant.
Once more did they congeal but this time they took on the form of a humanoid; Using magic to thread their consciousness into bodies.
These were the first Waves.
While in Humanoid form, they found themselves capable of reproducing but not like they themselves had done; While they had come from their own waves they now required the soundwaves of two Waves to create a new one.
These new Waves they spawned were different.... They were stronger.
They were capable of manipulating sound waves in any way they wanted and were capable of higher level magic; They were true Waves.
These are the Waves known today.
Most sages regard Waves very lowly, believing them to be mere copies of themselves that some sentient sound made.
Key Powers and Skills
The key skills of a Wave are their skills in sound manipulation; Not only can they affect sound naturally they are also capable of manifesting it into various attacks by imbuing magic into the waves. Most Waves use instruments as 'focuses' so to speak since attacks and skills are easier to manifest when put to music.
Waves are also known for being somewhat capable in AM fields, due to their abilities with sound waves. So long as they have sound waves around they are capable of using their power.
Wave Sages are also capable of turning into their true form of magical sound, becoming insubstantial and capable of resonating through almost anything.
Alongside all else, Waves can hear on a considerably higher spectrum than other beings; On frequency and loudness. They can also perform echolocation.
The main downside of a Wave is that it takes a lot out of them to use their abilities in space or other vacuums in which sound cannot travel because they then have to resonate through solid objects or use magic to resonate their sounds through.
Reproduction
If two full Waves reproduce, they enter their true forms and resonate through one another; Creating a new being. If it is a full wave and any other race, they simply mate in humanoid form. Half waves, as their true form is the form of their non-Wave parent they mate in their humanoid form aswell.
To kill a Wave, one would either need to eliminate them in their humanoid form faster than they can enter their sound form or think of a way to eliminate them in their sound form.
That seems like everything, do let me know if its approved or not.