Ryuji Ikeda (池田 竜次 Ikeda Ryuji) is the leader of Team Spiral and referred to as Zero. Ikeda's family staff a temple - moreover, his father is the temple's head priest and as a result has ample funds to finance his racing career.
Ikeda is an older racer and is very calm and level headed even in the heat of a race. He prepares for races by zoning out. Ikeda believes in a theory he created known as "Zero Theory" in which car and driver come together to become a single entity. To do so, a great deal of tuning has to be done to a car in order to match the characteristics of the driver to attain a higher level of racing.

(Source: Wiki)