Yellow Radio is the Yellow King and is the leader of the Yellow Legion, Crypt Cosmic Circus.
Yellow Radio, being the Yellow King, makes him a very powerful and commanding person. He is also very cruel and manipulative person as he was suspected as the one who stole the Chrome Disaster armor and essentially created the fifth one in order to exploit the rules that allows him to kill the Red King.
Yellow Radio appears along with his legion in the neutral field to kill the Red King, Scarlet Rain who is currently trying to stop Chrome Disaster with the help of Nega Nebulus. He openly states that Chrome Disaster has killed several members of his legion and as the rules state that if that legion is unable to kill the traitor, someone from the legion must be sacrificed instead. However, Scarlet Rain and Silver Crow suspect that Yellow Radio was behind the whole incident of the fifth Chrome Disaster to eliminate Rain to get to Level 10. As Yellow Radio chooses to kill Scarlet Rain, Silver Crow and the others decide to help her. Before the fight begins, Yellow Radio is able to incapacitate Black Lotus by simply guilting her on the crime that she committed which was the death of Red Rider, the first Red King.
Scarlet Rain and the Nega Nebulous attempt to run as the Yellow Legion starts to open fire on them. Silver Crow activated his wings, but Yellow Radio used his Silly-Go Round move on him to confuse him. When Cyan Pile was destroyed, Rain activated her Immobile Fortress. Yellow Radio encouraged his legion not to be afraid, ordering them to tear the fortress apart. Despite the Red King's overwhelming firepower and assistance from Silver Crow, they were just two against a whole army, which slowly wore them down.
During their fight, Black Lotus was able to recompose herself and defeated the Burst Linkers that were attacking Scarlet Rain. As she came to face Yellow Radio, he asked if she doesn't feel any guilt for beheading Red Rider. He jokingly wonders where their friend is now and what he's up to, whether he remembers the Accel World or not. He admits if he were in her shoes, he would never do something like that again nor forget. Black Lotus confessed that while she does feel guilt, she won't feel any from fighting him and fights one on one with Yellow Radio. With the two of them fighting on equal power, they each await for their special moves to recharge. As the both of them prepare to use their moves, they are interrupted by the appearance of Chrome Disaster who has pierced his weapon into Yellow Radio's abdomen. Initially being shocked, Yellow Radio decides to retreat. After Chrome Disaster is destroyed, Yellow Radio avoids implication in its creation.
Yellow Radio appearances is heavily based on a Jester. His attire consists of a yellow jester suit with two horns. He also wears a white mask with a pink mark on the left eye.
Yellow Radio's abilities rely on illusions in order to disorient his opponents. However, since he is the Yellow King, he is able to battle Black Lotus on equal grounds. His weapon is a baton that is apparently strong enough to withstand strikes from Black Lotus' blades. It was possible due to its special effect which is the more times it spun around, the more powerful it becomes.