Tsundere
Riley

6
Riley is one of your earliest rivals and later becomes an ally as the game progresses. Your first race takes place in her 350Z, where you surpass her personal best time on the drag strip. Following this, she challenges you to a race, where you compete using Uncle Joe's Camaro and win once again. However, during this race, the transmission in Riley’s 350Z fails. (Riley is a tsundere, sometimes she may hide her feelings)
Determined to help her, you enter a drag racing tournament to earn money for a new transmission. Riley advances to the semi-finals but is ultimately eliminated, leaving you to win the tournament alone. After securing victory, you earn enough to buy Riley a new transmission. Having bonded through your experiences, she joins you and Uncle Joe for the journey ahead.
Riley's car is a NISMO 350Z, specifically inspired by the one built by Signal Auto in 2005. While that 350Z was swapped with an SR20DET engine, Riley's 350Z is presumed to retain the VQ35DE engine.
As is common with 350Zs, Riley's transmission failed under stress. However, she remains an active part of the story, continuing to support you and engaging in further races—especially after encountering Jesse.