Mushu was once a guardian spirit of Mulan's family, but he has been demoted to the humiliating position of an incense burner and gong-ringer for the deceased Fa 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.
Mushu is one of the Scouts searching for refugee or anykind of life that survived from destroyed world, it is possibly that he once a cadet from Sentinel academy due to his inexperienced to battle a bigger or powerful villains.
he still close and consulat Mulan when she needed to cope a strange apocalyptic world.
he also appearing in the Ultima major story when the Ultimaswordwielder first arrived and even in a quest for finding Chaos Emerald before the Orgs find them first.