Kintaro belongs to the Shokan, a race of towering half-human, half-dragon hybrids known for their massive strength and their extra pair of arms. He makes his first appearance in Mortal Kombat II after the defeat of his compatriot Prince Goro in the previous tournament, and like Goro he is an enforcer for Shao Kahn, being the final obstacle Earthrealm's warriors must overcome before taking on the Emperor himself. He is portrayed in his debut as being even more fearsome than his predecessor, and his appearance reinforces this. While Goro wore little save his signature yin and yang briefs, Kintaro sports an intimidating pair of spiked shoulder plates, spiked bracers on each of his four arms, and a set of knee protectors.
The most notable aspects of Kintaro's design are his many tiger-like qualities. Initially, his appearance included tiger striping all over his body. Though this seemed to be mainly a cosmetic choice to differentiate him from Goro, when he later appears in Mortal Kombat: Armageddon, he is given further feline properties. Along with his stripes, Kintaro now possesses fangs, in addition to claws projecting from his hands and feet. Furthermore, his eyes appear more catlike, and most interestingly of all, he now has feet which resemble the padded feet of a tiger rather than the normal two-toed Shokan's feet. It is unclear if this is a sign of vast genetic variance among his race or if Kintaro's features were unnaturally created. Either way, Kintaro is unlike any other Shokan in Mortal Kombat to date.
After hearing that Goro had been killed by Liu Kang and his Earthrealm companions, Kintaro is so enraged that he vows to personally punish them in the next tournament. Acting as Shao Kahn's bodyguard, Kintaro places himself directly in the path of Raiden's champions in order to mete out his own style of Outworld justice, thereby ensuring that none will have the chance to challenge the Emperor. Despite being larger and more brutal than his comrade, Goro, he is ultimately defeated as well, followed soon after by his master.
Kintaro's Armageddon storyline is regrettable rather vague, doing little to account for his activities after his upset in Mortal Kombat II. It is stated that he "has served Shao Kahn for many years", though in what capacity it is not revealed. Presumably he enters the Battle for Armageddon to assist the Emperor in defeating the Forces of Light once and for all.
The mighty Kintaro has only two canonical appearances, and being an unplayable boss in one of them, this leaves him with a single ending. Fittingly for one who favors brute force, when he wins he is granted even more power with which to intimidate the enemies of Shao Kahn.
Mortal Kombat: Armageddon (non-canon)
After besting Blaze in single combat, a mysterious voice offers Kintaro a set of four enchanted swords which can be imbued with the powers of anyone he chooses. After Kintaro selects the powers of fire, ice, chaos and order, the blades seek out and slay Scorpion, Sub-Zero, Havik and Hotaru, stealing their souls. With the abilities of these warriors at his command, Kintaro is unstoppable, killing any foolish enough to challenge him.