You automatically get to Sky Island after you get the weather cuckoo to the hermit.

Island Challenge
Blast’em: Kill an enemy with a laser beam
100 diamonds.

Scholar: Study the Arcadian History
250 Diamonds.

Champion from Below: Clear the entrance to Grand Core
500 Diamonds

Chest
1. Next to the statue: 3 Arrows
2. Shortly inside the locked cave, you will find 10 bombs.
3. Turn left after you get in Grand Core for 10 bombs.

Bloodstone
1. Accessible when you first arrive on the island. Use the bomb to blast the path to the platform below.
2. Turn right shortly after you enter the Grand Core.
3. Inside the room where you get the Shield of Cronos, near the bottom right where you have to use jump to get to.
4. After you turn on the cooling fluid. (Pass the laser beam reflection), it will be next to the key chest.

Your Visit
Remember to look through the scope and unlock the location to Home Island, Graveyard Island, and Old Fortress if you haven’t.

Light up the torches inside the study and stand in front of the statue for the treasure to drop. Once you get through to the locked door, push the statue to the corner.

While inside the cave. Use the bomb to blow up some dirt some that you can move the box.

Grand Core
If you are stuck inside Grand Core, consider using the bomb to blow up the left path so that you can jump across.

To get the shield of Cronos, you will need to hit the switches, there is another switch that doesn’t usually look like one. You will have to be really fast to jump through the pillars. Consider prepare the field and toss the vases instead of using force spell.

With the shield of Cronos, you can use it to reflect the light and laser beam inside the room with two fire status and laser.

-Cooling Room.
If you are stuck here and cannot get the treasure box to appear. Consider back tracking to the other side of the room. There is a button where you have to place a vase so that the the chest appears and stays. The game calls it “Emergency” key.

Shadow Mesmeroth:
Below are some tips if you are having trouble defeating the boss.

Phase 1: The Shadow Mesmeroth will launch a fireball towards you. Simply put up your shield to reflect the fireball. When the boss gets damage by the fire ball, he will hide in three energy balls, you will have to find the right one to deal tons of damage.

Phase 2: Shadow Mesmeroth stand away to heal while laser cannons start shooting at you. Run to all four corners to stop the engine from running.

Phase 3: He stars shooting two fire balls at the time, use the same tactic as phase 1.