mix millefiori/splash/grigioperla

You becamed this result because of the Dominace of the ground-color genes.
The millefiori have as ground-color "eb/eb"
The grigioperla and the Splash have as ground-color "E/E"
When you cross "eb/eb" with "E/E" than the chicks have "E/eb" and that one "E" is Dominant over the "eb".
When you cross "bl+/bl+" with "Bl/Bl" you become "Bl/bl+" which is Blue.

PS : I am as mortal as you and everybody else