Mushu

Mushu appears as a summon in Kingdom Hearts, as a Magic Card in Kingdom Hearts: Chain of Memories, and becomes a member of your party in, along with Mulan, Kingdom Hearts II. Mushu is a tiny dragon who serves as the guardian and tutor of Mulan. He is a small red dragon with limited abilities, but is capable of breathing out tremendous fireballs. Mushu is headstrong and boastful, but knows very well when to shut up.

Kingdom Hearts
In Kingdom Hearts, Mushu escaped the destruction of his world and became a Summon character for Sora and is the last to be obtained. After the death of Maleficent in her dragon form, the Fireglow is left behind. When delivered to the Fairy Godmother, she allows Sora to use Mushu in battle. Mushu is one of the stronger of the Summons, capable of continously shooting fireballs from his mouth. He returns to his world when it is restored.

Kingdom Hearts Chain of Memories
Mushu appears as a summon in Kingdom Hearts Chain of Memories. His card can only be obtained after defeating Maleficent in Hollow Bastion. His main attack is shooting fire balls as in Kingdom Hearts, but by leveling up Sleights he can learn his ultimate attack Mega Flare which is attack the Bahamut summon uses in the Final Fantasy Series.

Kingdom hearts II
Mushu returns in Kingdom Hearts II but not as a Summon. He is Mulan's guardian in the Land of Dragons, one of the first worlds Sora, Donald and Goofy visit. Mushu is mistook for a Heartless at first due to his giant shadow cast on a rock. He is shocked to see his old friends in his world and introduces Mulan to them and explains her situation. Mushu's attempts to teach Mulan to act like a soldier aren't very good, making her walk oddly and even contributing to a brawl starting.

Mushu accompanies Mulan, Sora and the others to the icy mountains when they are attacked by Shan Yu and his army of Heartless. Mulan sees a way to defeat the army by causing an avalanche. She grabs a missile, lights it with Mushu and then launches it to a nearby mountain, Mushu accidentally going with it. He later returns and accidentally gives Mulan's identity away to Captain Shang who leaves her behind. Mushu dreads returning to face his fellow spirits, but knows he must. Shan Yu and a few Heartless reveal to have survived the avalanche and head for the Imperial City to capture the Emperor. The heroes race to save the Emperor and defeat Shan Yu. Mushu blurts out to the group unintentionally he is actually not a guardian anymore and is chased by Sora and Donald in a fit of rage.

Mushu returns during Sora's second visit to help battle the Storm Rider Heartless. However, he only serves as a battle ally and does not have any lines of his own, nor does he appear in the cutscenes.

In battle, Mushu can be used in Mulan's Limit move, launching a series of fiery attacks at foes which ends with a downpour of large fireballs.

Origin
Mushu first appeared in Disney's Mulan. Previously one of the twelve guardians of the Fa Family, Mushu was reduced to a summoner of the spiritual ancestors by banging a gong, because his advice led one of Mulan's ancestors to his decapitation. Mushu manages to sneak out to help Mulan bring honour to her family when she goes to join the army, claiming himself to still be a guardian.