
Although the director of the series, Tetsuya Nomura, has stated
that there are no in-game relationships, there is evidence to
support a theory of love between Sora and Kairi that goes past
common friendship. There is argument that they are merely best
friends, but according to evidence shown in the game, Sora and
Kairi might both have some romantic feelings for each other.
Although it is entirely mutual, here is some of the evidence from
Kairi's side:
During the sunset before the Heartless invasion of Destiny
Islands, Kairi tells Sora "Don't ever change."
When Sora sacrifices his own heart to restore hers, Kairi is
visibly shaken and refuses to believe that Sora may be dead,
shouting "No, he can't be. I won't let him go!"
During their escape from Hollow Bastion on the first visit,
Kairi hugs Sora (who is still a Heartless) to protect him while
she, Donald, and Goofy are attacked by numerous Shadows.
When Sora decides to go back to Hollow Bastion for Riku, Kairi
gave him her lucky charm and tells him "Don't ever forget.
Wherever you go, I'm always with you."
In the ending sequence to the first Kingdom Hearts, she
is genuinely moved to tears after seeing that Sora had made the
drawing of him extending a Paopu Fruit to her in their Secret
place. After that, she draws herself giving Sora a Paopu
fruit.
Throughout Chain of Memories, though she doesn't
physically appear, her image spurred Sora on and even Naminé said
that she was "the one he truly cared for" when she apologized for
re-writing his memories of her.
She wouldn't go to the small island until she remembered
everything about Sora.
Almost immediately after her communication with Roxas, she sent
adrift to sea a letter she wrote for Sora the day before.
After telling her story to the Twilight Town Trio, Olette
comments "What a romantic story!"
While imprisoned in World That Never Was, she blamed herself
for the Organization going after Sora.
When trying to escape with Naminé and asked by Saïx if she
wanted to see Sora, she replies "I do, more than
anything."
When she finds Sora, she attempts to attack the Shadow
Heartless unarmed while trying to assist him.
When they reunite, Kairi quickly runs over and hugs Sora to
make sure that he is really there.
Shortly after, if a player talks with Kairi, she says "I wanted
to see you so badly. I missed you so much!" to Sora.
While escaping from the Castle That Never Was, Kairi tells
Roxas and Naminé that she and Sora will be together every day.
Here is some evidence from Sora's side:
Riku tosses Sora a Paopu fruit and says "C'mon, I know you
wanna try it," after explaining the legend.
He became visibly flustered and embarrassed when Riku said that
the winner of their race would share a paopu fruit with Kairi, and
gave Riku a dirty look afterwards.
He draws himself giving her a Paopu fruit in their Secret Cave,
which is a symbol between lovers on their world.
He willingly stabbed himself with the Keyblade of People's
Hearts to release Kairi's heart, knowing what would happen to
him in the process.
Upon being restored by Kairi from his Heartless form, Sora
tenderly embraces and thanks her.
After sealing Kingdom Hearts, Sora tells Kairi "I'm always with
you too. I'll come back to you, I promise!"
When Sora, Donald, and Goofy first go to The Pride Lands (they
turned into animals, Sora was a lion cub) Donald said to Sora, "If
Kairi saw you she would think you were cute!" and Sora
blushed.
In Riku's story of Kingdom Hearts: Chain of Memories, a
cutscene shows Larxene telling Naminé that her work will eventually
make Sora forget about Kairi. Naminé states, however, that his
feelings for her will only grow stronger.
When Naminé admits that she and Sora were never friends, Sora
sadly replies, "We were never anything... more than that, either";
as Sora's memories of Kairi had been replaced with false ones of
Naminé, his feelings for Kairi had effectively transferred to
Naminé.
In Kingdom Hearts 358/2 Days, Xion takes Kairi's form
because of Sora's strong feelings for her.
During Kairi's telepathic meeting with Roxas, he tells her "I
know you. You're that girl he (Sora) likes."
He blushes after seeing Will and Elizabeth hug in Port Royal,
thinking of Kairi. Donald and Goofy notice this and tease him, and
he covers his face in embarrassment.
He becomes deeply saddened when he hears of Kairi's kidnapping
by Axel and blames himself for allowing it to happen.
During the Heartless Invasion of Hollow Bastion, Sora gets down
on his knees and begs Saïx to take him to Kairi. Beforehand, Saïx
asked "Is she that important to you?" and Sora replied "More than
anything."
He imagines himself dancing with her after the second visit to
Halloween Town.
When they reunite in the World That Never Was, Kairi quickly
runs over and hugs Sora, who hugs her back after recovering from
his shock.
In the World That Never Was, as Ansem sacrifices himself, Sora
attempts to protect Kairi from the bright light by wrapping his arm
around her.
She is frequently identified as his most important person, and
his light.