Shion Kiba

Shion Kiba is one of the main characters of the Cardfight Vanguard G. As the heir to the Kiba family fortune he was brought up to be a man befitting the upper class. One day his fencing classmate lost a card which Shion accidentally destroyed. During a trip to a card shop to buy a replacement he noticed a Blue Sky Knight Altmile on sale. This was the catalyst for Shion becoming a cardfighter. His vanguard circle is blue. He is also the former rival of Chrono Shindou. Source: Cardfight Vanguard Wiki