Ruler of the Sky

The Ruler of the Sky (スカイルーラー) is a Heartless Boss exclusive to Kingdom Hearts 358/2 Days. When Captain Hook and Mr. Smee dig up a treasure chest decorated with a dragon skull and buried next to a golden sword, the pirates' darkness awakens the Heartless that lays inside. The Boss then challenges Roxas while the Nobody explores Neverland. Upon its defeat, the Ruler of the Sky plummets into Captain Hook's ship, crushing it. As the Heartless Boss fades away into the light, the heart it held prisoner is finally released. Ruler of the Sky is fought on Day 301.

Kingdom Hearts 358/2 Days
You need to destroy all the tail segments of this avian Heartless to reveal its core. ''After each segment is destroyed, the Ruler of the Sky will glow red and charge its foes. Wait too close to the water's surface and it will fire a salvo of water shots.'' Once the core is exposed, avoid the spray of coins and counter with Fire magic.

Kingdom Hearts 358/2 Days
Right before you battle the Heartless, Pete shows up and explains his plans of his heartless army and threatens that his Heartless will gobble Roxas up for ruining his plans in Agrabah.

Strategy
The important thing to remember when facing the Ruler of the Sky is to not underestimate the Boss's true power. At the start of the battle, immediately Lock-On to the Heartless Boss. You must chase it around while airborne making your glide level may help chase it, also, equiping a long reach/midair may. Attack whenever possible. Be careful if you find yourself behind the Ruler of the Sky, as it will fire balls of energy from the cannon on its belly/tail. As the Ruler of the Sky's HP diminishes (to about half a bar per segment, it begins to glow with a pink aura. It may emit a sudden burst of energy when you are at close range. It also drops homing energy balls with rapid succession. The Ruler of the Sky also causes geysers to erupt from the sea below, which damage if touched. It also dashes towards you, dealing damage if it hits, going behind a rock may help. That is why it is important to keep your distance from the Heartless until it settles down.

The Heartless Boss will dive into the ocean after it has settled down. When this occurs, wait for it to resurface. Make sure you are out of its range, as the Ruler of the Sky will then quickly fire coins from its treasure chest-like mouth. The Boss is stationary during this time, so it is possible to deal damage with either the Fire Spell or even the Keyblade if you wish to take a risk. The process of battling this Heartless Boss then repeats itself from the beginning.

The Ruler of the Sky has yet another attack, an ability that makes use out of its sword - like wings. Turning its wings into claws, the Heartless Boss will proceed to slash you. This attack can be used to your advantage, as the Ruler pauses for a few seconds afterwards, giving you an extra opportunity to deal damage. It will also continue to deal impact damage as it flies by. This happens when all of it's tail falls off.

As always, equip as many healing spells and items as possible before entering this battle and this time, perhaps make a separate deck that has a TON of fire spells as it chases it and heals. Sometimes, when you are hit some of the Boss's health will be restored. Make use of your Limit Break, and it's a good idea to use a power-based weapon, as the Ruler does not stay still long enough for combo-based weapons to be effective.

As another option, try this. Get about ten Level 5-Cura spells and many Level 5-Fire spells. The battle will start with the Ruler of the Sky flying around in an oval-shaped path, but will occasionally go off path to stay away from you. You fly a little faster than it, so it will take time to get to the tail. Get a little ahead of the tip of the tail, and then attack. Using Fire magic will be useful as Fire will home in on to his tail. Keep repeating Fire or Keyblade combos to get damage done. The Ruler of the Sky will also blast a few mild-homing energy balls. Just move right left, up or down to dodge. Plus, every several seconds, a circle will appear behind him in the water. Move out of the way fast, because it becomes a ice pillar and can damage by hitting it.

When the Heartless has lost half of one bar or has had a bar finished, it will glow yellow and turn red. It will then continuously ram you. If it hits you you will lose about ⅛ of your HP. To avoid it, just keep holding the right button and move up and down when it starts shooting towards you. It will then plunge into the ocean. After it pops up, it will shoot coins out of its mouth. Make sure before or during its shooting, you stay below the range of the attack. if you want, you can try to attack. It will then repeat the first and second step, with another attack to come when its life it depleted to about half.

When you completed defeating half of the Heartless, it will make the water shoot up in bars again, but with more coming from every where. Now, it will fly in a big circle, shooting energy balls every few seconds. Just dodge the same way you did the first time. The battle with the Ruler of the Sky is perhaps the longest boss battle in Kingdom Hearts 358/2 Days, so come prepared with enough restoratives and abilities. It helps to have a large stock of high-potions and ethers.

Trivia

 * The Ruler of the Sky resembles many things commonly associated with pirates, such as treasure, swords, parrots and skulls.
 * Interestingly enough, if you are hit by the boss's coin shot attack, you will recieve Munny.