|Difficulty Level||Hit Points|
|Pink on the Inside||3200|
"The guardian of the gates of madness is a two-headed, fire-breathing, gut-chomping mastiff. By the time you reach its domain, rest assured that it will know of you and be ready to tango in the worst way. Remember that two heads are better than one--and you'll have to deal with both." — Blood Beastiary
Cerberus is a large two-headed dog that acts as the third major boss of Blood, responsible for guarding Ishmael. Although there is no definitive evidence, this creature appears to be the progenitor or guardian of the Hell Hounds, just as Cheogh is for Gargoyles and Shial for Spiders.
The name Cerberus comes from the Greek mythological creature, a satanic dog with three heads that guarded the gate to Hades, although this creature has three heads and a tail full of snakes which helps it to kill anything that comes from behind it. It can kill both enemies that come from the front and from the back. Also, in appearance he more closely resembles the two-headed Orthrus, who was said to be the brother of Cerberus who guarded Geryon's cattle and was killed by Heracles. Their parents, Echidna and Typhon, are referenced as boss characters in the fan add-on Bloody Pulp Fiction depicted as Cerberi. (Note that a Cerberus with two heads, being dicephalic parapagus twins, would be more scientifically plausible than one with three.)
When Cerberus is killed, Caleb slices open its belly with his pocketknife and stuffs it full of Remote Detonators. He walks away and presses the flashing button, causing an eruption of blood and guts, drenching Caleb in blood. With the camera focused on his red eyes, he comments "Rest in pieces" with a morbid grin.
It attacks by spitting balls of explosive napalm from a distance, and emitting bursts of fire. At close distance it can bite with its large jaws. This rarely encountered and fearsome creature attacks by breathing burning balls of explosive napalm at great distance or small fiery clouds of fire at medium range and by biting/devouring its enemies at melee distance.
The most effective weapons against Cerberus are dynamite bundles and the Tesla Cannon. Holding down the secondary fire of the Shotgun will stall Cerberus and kill him in a short amount of time. When the monster's health reaches around half or 49%, one of its heads will droop down dead; however, once this occurs, the remaining head will attack with more ferocity.
Cerberuses do "infight" in the Doom sense; on E4M8: The Hall of the Epiphany, if Tchernobog hits the Cerberus, it will forget about Caleb and fight back the dark god. If the player is skillful enough to make this happen, the final fight will became far less difficult and shorter.
"Named for the mythical guardian of the gates of Hell, this two-headed firebreathing demon abides in a dark, sulfurous den, hidden to the world of mortals. Ferocious and nigh invulnerable, Cerberus is the deadliest adversary you will face aside from Tchernobog himself. Remember that you must destroy both heads in order to defeat him." — Blood Manual
Cerberi are encountered three places in Blood: once at the end of episode three, once in the middle part of E4M7: In The Flesh (Extra Crispy only), and once at the E4M8: Hall of the Epiphany. Cerberus can also be seen in the opening movie, bursting Ishmael into flames. There is no explanation why other Cerberi exist, when the manual indicates there is only one Cerberus character. Models for the other bosses are explained as being Stone Gargoyles or Mother Spiders. There is no indication that there are any other creatures which resemble Cerberus.
In Cryptic Passage, the final boss is two Cerberi found past the portal to an "otherworld" in CP09: Castle, although the manual describes it as another entity labeled "The Lord of All Nightmares" which guards the scroll. It is quite possible that the Lord of All The Nightmares has some kind of conection with The Nightmare, or both are the same being, but it was never confirmed. This new character also could be named after the Lord of Nightmares from the Slayers franchise.