Little is known about Ashitaka's past, but it is known that he is the last prince of a dying Emishi village who at some point he became engaged to Kaya. It is unknown what happened to his parents, but given the fact they are never seen at all, not even when the village wise woman Hii helps Ashitaka with his curse; it can be assumed that they are dead.
Ashitaka for the most part displays, a calm and serious demeanor. In spite of this, Ashitaka is by no means jaded and bitter as he is a kind and self-sacrificing individual, who would willingly help complete strangers. He also can be playful and laid-back as shown by his reaction to the possibility of the Kodama, leading him and the injured Iron Town men the wrong way. He is also to display a certain degree of humor and wit, as shown when he remarks that happy women make a happy village in Japanese culture, despite the fact that the women he was referring to were spoiled and pampered by Lady Eboshi.
Despite being a trained warrior Ashitaka is an occasional pacifist who values lives, regardless of whether or not they are his enemies, as such he prefers to reason with his opponents and avoids killing if he can help it. But, when all else fails, Ashitaka does not hesitate to kill showing a sense of practicality.
While fairly composed, Ashitaka does have a temper and it is only made worst by his curse which prompts him to act on his darkest thoughts when enraged. Fortunately, this is prevented by his sense of restraint that allows him to control himself in spite of the overwhelming power of the curse, which had previously caused him to kill a bandit.
Role in the film
Ashitaka is first seen riding towards the lookout tower on his mount Yakul, delivering Hii's warning to return to the village to everyone he meets along the way. Upon meeting Jissan the watchman, Ashitaka is informed of something coming towards the village which revealed itself to be a massive demon boar covered in black worms that destroys the lookout tower but, not before Ashitaka and the watchman escape. Mounting Yakul but not before being warned by the watchman to avoid being touched and cursed by the demon, Ashitaka pursues the demon to prevent it from reaching the village. At first he tries to reason with it, but when his pleas go unheard, Ashitaka releases an arrow that strikes one of its eyes. And the demon seizes his arm out of rage but Ashitaka, managing to escape its grasp, releases another arrow into its second eye, felling the demon.
After he is dismounted, Ashitaka's wound is tended to with some water after which, he meets with Hii and the village elders and Ashitaka is informed of his impending pain and death from the demon's curse. And that the only way for him to be healed was to go west in the direction the boar came from. Along the his travels, he stumbles upon a village under attack by ruthless samurai warriors and yells at them to stop what they are doing. In doing so, as he aims an arrow at one of them and his arm pulsates as he releases the arrow and it hits the samurai perfectly in the arms, cutting them both off. When two more samurai pursue him, he draws another arrow and points it at them, warning them to let him pass. Again they shoot at him, and again, he fires back, and this time, his arrow hits the second samurai in the head, taking it clean off. Ashitaka escapes to another part of the village.