Blood for the blood god is part of the popular battlecry of Chaos Space Marines in Warhammer 40K, sometimes followed by the words “skulls for the skull throne”.
Online, the phrase served as the inspiration for many memes, appearing as the caption of image macros, as well as the template of humorous phrases
The first edition of Warhammer 40K was published in September, 1987, featuring the Chaos Space Marines faction, who worship Khorne, a god of chaos.
In the fantasy world, Korne is a god associated with war, homicide, anger, hatred and blood, which spanned the battlecry of Chaos Space Marines; “blood for the blood god!”.
An early explanation for the battlecry was added to the Wikia page of Khorne in 2006.