Kamen Rider Skull (A.R. World)

This Kamen Rider Skull (仮面ライダースカル, Kamen Raidā Sukaru) is a version of Sokichi Narumi (鳴海 荘吉, Narumi Sōkichi) from an A.R. world, and is the Decade version of both Skull, and Kamen Rider Double.

History
His card mysteriously ended up in Tsukasa's possession but sealed, It was used (without Decade's powers) after the battle with Super Shocker by automatically unsealing itself and summoning the A.R Skull to Shotaro.

He met the prime reality Shotaro Hidari, Philip, and Akiko Narumi after Tsukasa Kadoya handed Shotaro a with Skull's image on it. This Sokichi Narumi came through a dimensional wall, praising Shotaro as well as (indirectly) giving him closure before returning to his world.