Keicho is the evil elder brother of Okuyasu, and one of the villains from the fourth arc of JoJo's Bizarre Adventure.
Twelve years prior to Diamond is Unbreakable, Keicho and Okuyasu's mother died, leaving their father in depression. On top of that, Japan had been going through a tough time economically and his family soon fell into poverty. Due to this, Keicho and Okuyasu were abused constantly.
However, two years later, his father started to receive letters with money and jewels. Much later in his life Keicho would realize his father had sold his soul and heart to Dio Brando, who, at that time, was scouring the globe for a stand user capable of recreating reality.
However, untrusting of Keicho's father, Dio implanted a seed of his undead body within him. When Jotaro defeated Dio, the seed burst causing their father to slowly mutate into a monstrous form, later losing the ability to speak. In this form, Keicho's father would heal any wounds inflicted upon him.
For many years afterward, Keicho searched for someone capable of killing his father. Keicho soon came across the bow and the stand arrow, shooting random people throughout Morioh in order to find someone to kill his father. He thought he found this in Koichi Hirose, but this only lead to a confrontation with Josuke in which Keicho was severely injured, and told Josuke about his family's history.
Josuke offered to heal Keicho's dad in return Keicho would give up the bow and arrow. Unwilling to do that, and with Red Hot Chili Pepper lurking behind Okuyasu, Keicho shoved Okuyasu out the way, being electrocuted to death.
Near the end of Diamond is Unbreakable, during the final battle with Yoshikage Kira, he appeared as a ghost to Okuyasu, questioning where he wanted to go, thus convincing him to live on.
Keicho's stand, Bad Company, is a complete miniature army composed of soldiers, helicopters and even tanks, all under his control. Like a real army, they act like real soldiers, using warfare tactics to fight. Destroying some soldiers will do nothing to Keicho (in his own words, it only ruins the formation), so the only way to defeat him is to attack Keicho directly.