A three-headed daemon feared throughout Niflheim. Although famously ferocious and seemingly impossible to tame, the imperial army nevertheless set out to capture and control the canine. The magitek infantry ultimately succeeded in suppressing Cerberus, but not before the beast wrought death and destruction upon the military and citizenry alike.
Cerberus is a creature in the Final Fantasy XV Universe. It is a colossal three-headed canine daemon. It is black with glowing eyes and claws, and it breathes fire. Cerberus has a scaly body with a long dragon-like tail. It is much bigger than most daemons, and according to the Final Fantasy XV bestiary, is 140.58 ft. long and weighs 596.32 tonnes.
Cerberus is a beast feared in Niflheim, suggesting it originates from the imperial lands. Niflheim deployed its magitek infantry to capture one, succeeding with great losses. In Kingsglaive: Final Fantasy XV, Nyx Ulric fights Cerberi in the outlands of Lucis, likely deployed by Niflheim.
In Omen, Noctis Lucis Caelum becomes surrounded by Cerberi in his nightmare. The once-lush land turns into a hellscape, and he fights Lunafreya who strives to hold him at bay, calling for him to come to his senses. As Noctis does, he realizes he has been led astray, and the dog he had been following turns black and scorched with flaming eyes like those of the Cerberi.
When Noctis and his retinue return to Insomnia after his ten-year absence, they find a sleeping Cerberus outside the Citadel, and presume it to be Ardyn Izunia's "pet" left out to guard the palace. It rouses and attacks the party, eventually enveloping the area in a wall of fire, blocking their escape. Cor Leonis arrives to subdue the beast and they take it down together.
A Cerberus boss appeared for footage of Final Fantasy XV shown at the Game Developers' Conference in March 2017. Cerberus was on level 47 and was fought in Lestallum. The boss is added to the Royal Edition and PC versions of Final Fantasy XV, now fought in the expanded Insomnia ruins. Cor Leonis appears to shield Noctis from the Cerberus's attack. The player can pick up Trihead Heart from the ground after felling it.