In this universe the True Cross requires every demon or nephilim in the Order to bond themselves to an exorcist as a familiar to join, and even the Demon Kings are not an exception to this. Mephisto has refused this rule for years, but this leaves him unable to get his claws as deep into the Order as he wants. So when Shiro comes to him after the death of Yuri Egin with Satan's children, the details of his favour change slightly.
4 parts