Mushu was once a guardian spirit of Mulan's family, but he had been demoted to the humiliating position of an incense burner and gong-ringer for the dead Fa family ancestors ever since he failed to protect a family member, a soldier named Fa Deng, resulting in the soldier's demise by decapitation (he's seen carrying his own head as a spirit).
In contrast to Mulan, Mushu is in most situations more comical, overconfident, and impulsive. He strives to be one of the family guardians again, and selfishly decides to convince Mulan to join the army to turn her into a war hero, believing this will get him back on the 'top shelf'. However, he comes to realize how selfish he has been, admitting to Mulan that he risked her life to further his own goals. He then intends to take her home to face the consequences of his actions, but when she insists on stopping the Huns, loyally follows her, showing that underneath, he has a good heart.
Mushu is rather sensitive about his size.
At the start of the film, Mushu does not make his official appearance until after Mulan runs away from home to serve in her elderly father Fa Zhou's place in a war against the deadly Hun army. Knowing that Mulan's exposure will lead to the disgrace of the Fa family, the spirits of the ancestors choose to send the Great Stone Dragon to simply bring her back safely. For the task of awakening him, they send Mushu, who is offended when he is not asked to find her himself.
After several unsuccessful attempts at waking the Dragon, he eventually ends up accidentally destroying the dragon statue. Cri-kee suggests that Mushu bring Mulan back safe instead so that he won't be punished, but Mushu decides to make his own plan and sets out to make Mulan a war hero, selfishly endangering her life. He meets her in a bamboo thicket overlooking the army camp. He poses as her powerful guardian though she is mildly impress because of his stature.
They team make way for the camp where Mushu continuously give Mulan (in the guise of Ping) advice on acting masculine. The advice eventually leads to a brawl which causes Mulan to become the most unpopular soldier at the camp. For the next couple of days, Mulan progresses along with the others in skills but the Emperor's adviser Chi-Fu feels the troops are still unqualified for the war. To keep his plan intact, Mushu creates a phony message alerting Captain Li Shang and the troops to head to the front immediately.
After a run in with the Huns, Mulan's secret is discovered and she is left on a mountain summit as punishment. Mushu then takes the time to reveal the real reason he decided to help Mulan on her mission, but apologizes and promises to stay by her side no matter what. Just then, Mulan spots Shan Yu, the leader of the Huns, making way for the city. Mulan, Mushu, Cri-Kee, and Khan makes way to the city to warn Shang. At the Emperor's palace, Mulan battles Shan Yu and comes up with a plan. She leads him onto the roof where Mushu fires a rocket at the villain. Shan Yu is then blasted to the fireworks tower and is killed in the explosion. Mulan is deemed China's bravest warrior and Mushu regains his job.
In the sequel, when Mulan prepares to marry Li Shang, Mushu is at first overjoyed to the point of tears, going as far as planning the wedding himself. However, things change once the ancestors tell him that if Mulan marries Shang, his family's guardians will take over for her, thus making Mushu a homeless dragon. Desperate to keep his job, he continuously tries to break the two apart to keep his position.
After many failed attempts, he finally succeeds. However, Mushu begins to feel regret and eventually tells Mulan the truth. Aside from this, Mulan and Shang were meant to escort three princesses to a kingdom for an arranged marriage with a childish prince. The princesses fall in love with Yao, Ling, and Chein-Po with Mulan supporting it after Mushu's schemes. To prevent the princesses from marrying, Mulan agrees to marry the prince in their place.
To redeem himself, and rescue Mulan, Mushu poses himself as a the worshiped Golden Dragon of Unity and forces the king to cancel the marriage, allowing Mulan and Shang to marry as planned. Back at home, Mushu prepares to leave his pedestool and return to gong duty but Mulan and Shang arrives at the temple and merges the family temples, thus allowing Mushiu to keep his job.
House of Mouse
Mushu appears as a recurring guest in the animated series and is usually seen with Cri-Kee. Mushu is usually seen having a comical comment about a performance. In "House of Genius" - Mushu showed his annoyance with Donald's voice and after the staff was replaced with robotic counterparts he claims the Robo-Donald to be much better than the real. In "House of Scrooge" - Scrooge Mcduck showcased his number one dime to the guest but Mushu was unimpressed and thought of it more as a bottle cap. In "Chip N' Dale". Mushu was the only guest to help Pete finally open his bag of nuts. In "Dining Goofy" - Goofy mixed up Mushu's order and gave him water resulting into Mushu losing his fire breathing abilities. In Mickey and Minnie's Big Vacation, he blames Maleficent from Sleeping Beauty for setting the place on fire.
Songs sung by Mushu
Kingdom of Hearts
In Kingdom Hearts, Mushu survived the destruction of his world, The Land of Dragons and became a Summon Gem. After the death of Maleficent in her Dragon form, the Fireglow Gem is left behind. When delivered to the Fairy Godmother, she restores his spirit and allows Sora to call forth Mushu in battle. Mushu is one of the strongest of the Summons, capable of continuously shooting fireballs from his mouth. He returns to his world when it is restored at the end of Kingdom Hearts.
Kingdom of Hearts 2
Mushu returns in Kingdom Hearts 2 but not as a Summon. He is Mulans guardian in the Land of Dragons, one of the first worlds Sora, Donald, and Goofy visit. Mushu is mistaken 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. Later, he then tells Mulan that he saw Shan-Yu in a cave, which turns out to be a trap.
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, with 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 in a fit of rage.
Mushu returns during Sora's second visit to help battle the Storm Rider Heartless. Although he is not used directly as an ally, Mushu is used in the last stage of Mulan's Limit move, launching a series of fiery attacks at foes which ends with a downpour of large fireballs.
- Along with Mulan, Mushu is the most iconic, and popular, character from Mulan.
- In the Disney Princess franchise, Mushu is the only sidekick of a Disney Princess to have a more significant role than the love interest.
- In deleted scenes, we see that Mushu is not only charismatic but has an amazing singing voice. He even had his own song named "Keep 'em Guessing."
- If "Keep 'em Guessing" wasn't deleted, Mushu would've been the second animal friend of a Disney Princess to have a song of his own. (The first being Sebastian, the third being Louis)/
- In deleted scenes Mushu, calls Mulan by various nicknames including "Miss", "Doll", "Babe", "Mademoiselle" and "Sweetcakes."
- In House of Mouse we learn his favorite foods are Kung Pao Chicken and fresh roasted nuts. Drinking Iced water prohibits his ability to breath fire for a little while.
- Japanese : Koichi Yamadera
- English : Eddie Murphy (first film), Mark Moseley (House of Mouse - Present)
all information on Mushu came from http://disney.wikia.com/wiki/Mushu