The Hunter Dragon is yellow in color and larger than the Scout Dragon, but smaller than the Alpha Dragon. Upon his death, he will drop 4 Dragon Scales and there is a chance he will drop a Dragon Head.
Note: All DragonRealm Dragons will only spawn in the Overworld. Their spawn is by chance only when chunks are loaded, so exploration is encouraged to increase your chances. They do not favor any specific biomes. The spawn chance and their attack/health can be adjusted in the config file.