Dreon is an optional boss, fought in the first hidden zone, Hidden Plains, on Ghiria. He is a big green dragon who loves to fly. He is not destroyed like the other bosses are, he flies away. You'll see him in the Ghiria hub area from there out. Watch out for his light orb attack- it's a one hit KO, but he only uses it on the very last slice of his health.
When he was little, Dreon didn't have the freedom that the other dragons had- he was raised by a cruel family of tigers, who thought his flight ability was unfair, and thus gnawed off his original dragon wings. Dreon sought the help of Dinio, who was kind and youthful back then. Dinio was the Ghirian tribe's sorcerer at the time, not the leader. Using a spell he had just conjured, Dinio created new wings for Dreon. However, these ones were feathered. Dreon was not happy. He came back to his family, and they were enraged. This time, though, Dreon flew away. His tiger family chased him to kingdom come, until Dreon shot a ball of light that formed a portal to the Hidden Plains. He flew in, and before the merciless tigers could get him and rip away his flight a second time, he shot another ball of light at them. They were completely destroyed. The portal was opened in an area well hidden from all others, and so, Dreon lived there all his life, soaring through the starry sky, protecting the beautiful creatures that lived there already.
Dreon will claw, bite, and swoop in battle. When he swings his head down to bite, use a heavy downward attack. He'll be stunned. You can then jump on his back and hit any of the three weakpoints. Once all three are taken out, Dreon is down.
Magolor Form 2's music from Kirby's Return to Dreamland plays in this fight. Listen: