Geronimo

You may be looking for the following: 
*Geronimo (Ghost) - minor character from Kamen Rider Ghost: The 100 Eyecons and Ghost's Fateful Moment
*Amakusa Shiro Tokisada - main antagonist of Geats Extra: Kamen Rider Tycoon meets Kamen Rider Shinobi whose monster form is known as Geronimo