Thunderbird

Thunderbird is the penultimate boss of Zelda II: The Adventure of Link, appearing in the Great Palace as the final obstacle before the Triforce of Courage's chamber. It appears as a tall birdlike figure with a large, feathered headdress and seems to fly by vibrating the feathers on a constantly aloft pair of wings. Unlike the other bosses, it lacks the boss music and takes a few moments to appear in its arena once Link arrives.

To attack, Thunderbird slowly flies back and forth while breathing out fireballs that arc downward at Link for a large amount of damage; however, contact with Thunderbird itself is harmless. The fireballs can be knocked back with the Reflect magic. At first, Thunderbird appears red and faceless, being completely impervious to most of Link's attacks. The player needs to use the Thunder magic to render Thunderbird vulnerable, turning it blue and revealing its lion-like face. As such, Link needs a large enough amount of magic before entering the battle due to Thunder's heavy cost. Once Thunderbird is blue, normal sword attacks will damage it, but it will continue to attack as before. Once half of its health has been lost, it starts breathing fireballs much faster in desperation. Once its health bar has been depleted, Thunderbird explodes, and the key to the Triforce chamber appears.