Bull King

Bull King is an antagonist of the classic novel Journey to the West and many of its adaptations. He also appears in Doraemon: Journey to the West as one of the main antagonists. He is one of the most popular Journey to the West villains, alongside his wife Princess Iron Fan and the White Bone Demoness.

Past
The Bull King is a demonic ox who befriended and being the sworn brother of Sun Wukong. He eventually married Princess Iron Fan and gave birth to the Red Boy.

Role in the story
Bull King first appeared as a disguise of Sun Wukong to trick Red Boy into release Xuanzang. However, upon seeing that this "Bull King" does not remember his birthday, Red Boy deduced that he is a fake one and blew his cover as Wukong. Bull King later appeared when Xuanzang and his companions arrived at the Fire Mountain, having married to Princess Jade Face (a demonic fox). Upon learning that Wukong had took away the Iron Fan from his former wife Princess Iron Fan, Bull King angered and swore revenge. He later disguised as Zhu Bajie to trick Wukong into giving him the Iron Fan. Angered, Wukong, along with Zhu Bajie (who angered due to Bull King disguised as him) fight the Bull King, forced him to revert into his true form to attack them. However, with the help of the deities, Wukong managed to defeat the Bull King and get the Iron Fan.

Doraemon: Journey to the West
Like other demons, Bull King is also escaped, along with his wife Queen Iron Fan, from the Journey to the West novel due to an accident caused by a gadget of Doraemon. He and his wife set up plans to eat Xuanzang, but eventually he was killed by Nobita (who he believed to be Sun Wukong) and thus disposed all of the magic that the demons caused. Queen Iron Fan, due to this, died shortly after by falling into the lava.

Trivia

 * Unlike most of other demons in Journey to the West, Bull King has no interest in Xuanzang, leaving alone eating his flesh. Ironically, in Doraemon: Journey to the West, he and his wife Princess Iron Fan (Queen Iron Fan in this version) are the masterminds behind the plan to capture and eat Xuanzang.
 * In addition to this, Bull King acts more as an antagonist than an outright villain, opposed to other demons in the story, as his ultimate goal is just to humiliate Wukong for what the latter had done to his son and former wife.