Fate/Extra-Miko-n!Kyasuko-chan!?
A manga spin-off of Fate/Extra CCC. Written by Takenoko Seijin and published since 2013.
The story is an alternate route to Fate/Extra CCC that focuses on Tamamo no Mae as Kishinami Hakuno's servant. It explains the background between Tamamo no Mae and Amaterasu, and the plot includes planned elements for CCC that were cut from the game.
This tag implicates fate/extra_ccc (learn more).