My concept is Kamen Rider Rekishi (Masked Rider Chronicle). The theme of the character is based on Knowledge and History, more so the 'warriors of legend,' such as the Spartan, Ninja, Pirate, Knight, Aztec, Rajput, etc. And yes, the idea came from the Deadliest Warriors t.v. show (cheap, I know, but I thought it sounded cool mixing two of my favorite shows in a unique way).
Chronicle is his base form shares similarities to Double, Ixa, and Decade in terms of armor. He wears a black, padded latex undersuit with chrome-blue and silver-lining armor (a reversed color scheme to Kamen Rider Tiger).
The Chronicle Driver has three uses; a primary state which Mashuu places his Initial Data Cube inside to transform into Chronicle, a secondary state that utilizes a Rider Card attachment and Rider Card called Transversal to transform into Alpha Chronicle, and a tertiary state that uses a Gaia Memory attachment and Gaia Memory called Fusion (absorbs Scion) to access Omega Chronicle.