Ryu is Ken's best friend from his childhood, as the two have trained in the same art of Ansatsuken for a long time and share the same sensei, Gouken. They share a very close bond and will help each other out no matter the cost. One can see that they deeply care for each other and never quarrel. Ken’s able to notice when Ryu isn’t in the right state of mind as shown in the Alpha series, where Ken gave him his red headband in order for Ryu to stay focused and not lose his way. 