Shichimyaku

The Shichimyaku (死血脈, Dead Blood Vein) is planetary network composed of blood from the countless wars what once plagued Earth. This blood is referred to as Shichi (死血, Dead Blood). When Shichi is used by someone, it is referred to as Black Blood (黒血, Kokketsu). This blood is not only contained within the earth itself, but also its atmosphere and is intertwined with and as plentiful as.