Hellhounds

What have Daemons for a pet? Hellhounds! These fiery dogs come from the same extradimensional plane as their masters and are quite dangerous. Immune to any fire damage thanks to their nature, their bites and fire breath can prove to be lethal. Also they act as bodyguards for their masters, shielding them from damage.

They are found near lava and in the company of Daemons.

They only appeared once, but that mustn't mean that they are new, as they could have simply not appeared in Britannia before. (Pictures of Hellhounds were seen in both Underworlds in the Void)