Ezlo
From Zelda Wiki.org
Ezlo is Link's main companion in the Game Boy Advance title The Minish Cap. He has the appearance of a green cap, like the one Link usually wears for his adventures, but with a face resembling a bird, with a huge yellow beak and cartoony eyes. Ezlo gives Link advice and background of the current situation throughout the adventure, both spontaneously and on demand, with use of the Select button. Ezlo's main use, gameplay-wise, is to shrink Link to Minish size whenever he nears a Minish Portal. He also serves as a parachute when Link jumps into whirlwinds, similar in use to the The Wind Waker's Deku Leaf.
Link found Ezlo in the Minish Woods being attacked, and after he saved him, Ezlo united with Link and he helped him on his quest for defeating Vaati and returning the Picori Blade to its former power.
"A strange creature that looks at first like a cap. He speaks roughly and treats Link like a child, but he actually really likes Link."
Ezlo's backstory
Spoiler warning: If you have not completed the relevant game(s), then the following details could spoil your experience.
Before meeting Link, Ezlo was a renowned Minish craftsman and sage, who was working on a cap that would grant the wishes of its wearer. When he finished the aforementioned Minish Cap, his apprentice Vaati (who was also a Minish at the time) stole it from his work desk and placed it onto himself, using its power to turn himself into the "most powerful sorcerer". Ezlo attempted to stop Vaati, but was unsuccessful. Vaati used the power he had recieved from the Minish Cap to curse Ezlo, transforming him into a creature resembling a cross between a green hat and a bird. Soon after, Link found Ezlo in the Minish Woods.
"The Minish Ezlo, before he was cursed by Vaati. He is famous Minish sage. Even among Minish inventors, he was reowned for his amazing creations."
Trivia
The game menu normally displays several Ezlo images as a background. With full health Ezlo appears with his beak open and held high. After losing health, Ezlo's image has a closed beak, held low. If Link only has one Heart Container of Health left; then Ezlo's image will appear exhausted.
