Kill colored Background Question

Sorrowhitx

Hello, i don't know if this is the right place to ask but,
I have already spent a lot of time into figuring out how to get this (Red/Blue/Green/Purple) Colors.
(safe Link of a picture of what i mean)
Is it a Ranked reward? or what is it.
I thank for every Answer!

{Mamy}

You must be lucky to see this early. Because I've been wondering and researching for a long time. No one answered or knew. But after a long search, I found and learned. It comes with a ranked reward, and the higher your rank, the more prominent the image.

Note: Not ranked ZM