They drink blood to live. Hunger as appetite.

Ingested blood reaches a restructured stomach whose parietal acid cells have been largely replaced by metalloproteases and haem oxygenases. Globin chains are cleaved for amino acids. Haem groups — each a porphyrin ring with a single iron atom at its centre — are isolated and sent via modified portal circulation to the liver, now the staging organ of the bio-voltaic cycle. Iron is extracted, loaded onto modified transferrin, and delivered to mitochondria throughout the body. The non-haem caloric fraction — plasma lipids, globin residue, dissolved glucose — is packed into dense lipid and glycogen stores in liver, omentum, and abdominal adipose. Those stores are the fuel. The iron is the ignition.

At the inner mitochondrial membrane the donated electrons are captured by a modified cytochrome chain and fed into the electron-transport apparatus. Glycolysis and the Krebs cycle are no longer the clock; they are not gone as chemistry. Stored lipids and glucose still oxidise. Fe²⁺ from fresh haemoglobin donates, becomes Fe³⁺, and is replaced at the next feeding. That is not a cycle closing. It is a catalytic reload, which is why the organism must feed. Efficiency approaches ninety-five percent. Baseline mammalian oxidative phosphorylation wastes roughly sixty percent as heat; a haemophage therefore runs cold and wrong on infrared — a reduced signature, not an absent one. Vanishing from thermal imaging is reserved for cryptobiosis, when bio-voltaic heat output falls to effectively zero. Blood is not a meal. Blood is a catalytic reload for a distributed biological fuel cell. A drive calibrated to iron has a metal sitting at the other end of the series.