Kingdom Hearts

Destiny Island:

 The Small Island where Sora, Riku, Kairi, Selphie, Tidus and Wakka play is a relatively small island, but is where most of the beginning of the story takes place. It is reached by canoe from the main island. Most of the island is covered in trees and shrubbery. The outskirts are naturally covered in yellow sandy beaches. There is a Seaside Shack and a somewhat treehouse built into a large tree. A miniature island is settled next to the island and can be reached by crossing a bridge (which can be accessed by using the stairs in the Seaside Shack mentioned above) (or alternatively, by swimming towards a ladder on the opposite side of the island, and then climbing it). Sora and Riku often practice their sword fights and where the friends can watch the sunset. On the miniature island, there is a crooked palm tree that grows Paopu Fruit. Local myth dictates that the two people who share one will have their destinies intertwined. The Cove at the back of the island has an obstacle course which Sora and Riku use during their competitive challenges

*The Secret Place

The Secret Place is a cave hidden behind the island's waterfall, where the children visited during their childhood. Sora and Riku first discovered it when they were young children. There is a door in the cave which is actually the Keyhole of the world. The cave's wall are covered in chalk drawings, some hinting at the earlier encounters of the children . Among them is a drawing of Sora and Kairi sharing a Paopu Fruit, as well as drawings of Donald, a chocobo, Disney Castle, and a monster coming out of a swirling ball. There's also a drawing on which you can see a dog facing a kid , this is most likely refering to the point where Pluto finds Sora in Traverse Town. Riku enters here near the beginning of the game and opens the door, unleashing the Heartless onto the islands. Whether he did so knowingly and willingly or not is not known, though it is likely that the words of Xehanort influenced him to do so

Destiny Island's characters: 

Wakka:

A boy who lived on the Destiny Islands. He looks out for Tidus and Selphie like a big brother. Nobody knows what happened to him after his island disappeared.

"Final Fantasy X"

Wakka is a resident of the Destiny Islands and a friend of Sora, Kairi, and Riku. He spends a lot of time with Tidus and Selphie, and treats them just as a big brother would. He and Tidus expressed their curiosity over the Secret Place, and were thinking of exploring it.

Like Selphie and Tidus, Wakka appears in Sora's Dive to the Heart on the Destiny Islands area. His question, "What do you want outta life?" also helps determine the leveling pace throughout the rest of the game. Sora can answer with either A) to see rare sights, B) to broaden my horizons, or C) to be strong.

He can be fought while on Destiny Islands. He uses his Blitzball to attack as he did in Final Fantasy X (thus requiring the player to deflect Wakka's Blitzball back at him), but this one lacking the bumps and Spiran script for the word "blitzball" of the original Blitzball. Nevertheless, this makes him, out of all the Destiny Islands and Twilight Town Final Fantasy characters, the only one to use the exact same weapon as his original incarnation.

Tidus:

A cheerful, self-confident boy who lived on the Destiny Islands. He considers himself a champ at everything. Nobody knows what happened to him after his island disappeared.

"Final Fantasy X" .

Tidus is a friend of Sora, Riku, and Kairi, and is a resident of the Destiny Islands, spending most of his time with Wakka and Selphie.

In Sora's 'Dive to the Heart,' Tidus appears in the Destiny Islands area along with Wakka and Selphie. His question, like the other two, determines Sora's leveling pace for the rest of the game.

Q: "What are you so afraid of?"

Sora can answer the question in three different ways. Either A) getting old, B) being different, or C) being indecisisve.

If Sora loses a practice battle with Tidus on the second day in the Destiny Islands, Tidus performs his victory pose from Final Fantasy X, namely, tossing his sword upward then catching it before swinging it to his side

 Selphie:

Selphie is a minor character in the Kingdom Hearts series, originally from Final Fantasy VIII. Selphie seems to be a typical "girlie girl", as she is carefree, fights very scarcely, and overall acts like a little girl. She also seems to be a romantic of sorts for when you talk to her a second time on Destiny Islands she mentions how romantic the Paopu Fruit legend is. Her romantic nature is heightened when Kairi tells her she is sending a letter to the "other boy", who turns out to be Sora - Selphie is rather charmed by Kairi's idea.

Selphie is a resident of the Destiny Islands and a friend of Sora, Kairi and Riku. She spends most of her time with Tidus and Wakka.

She is one of three to ask Sora a question that helps determine his leveling pace during his Dive into the Heart in the Destiny Islands area. Her question, "What is most important to you?" can be answered with either A) being number one, B) friendship, or C) my prize possessions.

Like Tidus and Wakka, you can challenge her to a fight for experience points. She uses a jump rope (a would-be toy counterpart of her original incarnation's weapon, a nunchaku) to attack, and is probably the fastest out of herself, Tidus, and Wakka. However, her attacks are easy to block and counter, which means more exp.

When the Heartless destroyed Destiny Islands, her whereabouts were unknown. The most possible answer to this is that she disappeared along when the islands were destroyed. But thanks to Sora, she was able to return along with Destiny Islands.