Initially, Ken seems to have an intimidating and eccentric personality, however it is revealed later that he is actually very shy and soft-spoken, when he uses his real voice to speak. Despite his shy attitude, he is shown to be very friendly and supportive. Because his parents travel often for their jobs, Ken never had an opportunity to stay in the same school for a long time, which resulted in him not being able to have many friends. He is also shown to get nervous under pressure easily. Going along with his shy personality, he is also quite sensitive. He is extremely talented as a ventriloquist, being able to speak as his hand puppets even in battle mode. He uses his two puppets, Keru, who is the more aggressive and outspoken one; Besu, who is the kinder and more gentle one, to portray his feelings on two spectrums. Because of this, it is difficult for others to figure out what Ken is thinking.

Shingo Aoi from captain Tsubasa!