From Team Lava Blog:
Caretakers sometimes train Dragons at night when nocturnal Dragons are most awake. One night during flight training, the Caretakers spotted a far off glow through the fields. The sky was dark with no moon and stars, so what could it be? When they braved the darkness to get closer, they discovered a new Dragon, which glows with the light of a lantern. Light up the night with the Wisp Dragon in Dragon Story!