Aya Kujo

Aya Kujo uses the Triceratops Memory to transform into the Triceratops Dopant and is an antagonist of the first two episodes of Kamen Rider W.

Kamen Rider W
Aya Kujo was once an officer in the FPD until she transferred to the LAPD with encouragement from her partner Masaki Mizoguchi, whom she loved.

However, after Mizoguchi mysterious disappeared, Aya returned to Futo and bought the Triceratops Memory to use to take revenge against the corrupt cops who killed Mizoguchi, Himuro and Ken Akutsu. Aya uses the Memory's powers to kill off Himuro and Akutsu, but the Memory soon begins to corrupt her and causes her to turn her revenge to the city of Futo itself. She was later defeated by Kamen Rider Accel using the AccelGunner's Gaia Cannon.

OOO, Den-O, All Riders: Let's Go Kamen Riders
In the alternate timeline where Shocker dominated the world, the Triceratops Dopant was one of the monsters who served the organization in the alternate 2011.