Uh..Does anyone know what type of name I could give this guy?

Info about him:
-His heart is encased inside that crystal. Each little coloured thingee is one of his lives. When they all turn purple, he dies.
-He once sacrificed one of his lives to save a generation.
-That little hair changes colour each time he dies.
-He can disguise himself as a colorful emerald (american is colorful)