Trollhound

Picture a hulking, hideous worg or dire wolf with hollow black pits for eyes, 4 to 6 feet tall at the shoulder and knotted with muscle. Its skin is a sickly blend of violet, gray and green, with tufts of bristly black or gray hair, and its lips, tongue and teeth are ink-black. A stench of rot and filth always clings to it. Infravision reaches 60 feet.

Packs charge in a disorderly rush, biting whatever they reach. A natural 20 means a lockbite on a limb: the hound deals damage automatically every following round until removed or the victim dies. Its jaws cannot be pried apart while it is conscious; it must be killed or knocked out for at least one full round first. One in ten carries a mundane disease of the DM's choice, with a 1% chance per point of bite damage to infect, or 2% per point during a lockbite. These chances never accumulate.

Trollhounds regenerate 1 hit point per round starting the very next round after being hurt. Fire and acid damage does not regenerate, but a hound that survives it recovers 6 hit points per day whatever it does. A single hound tracks like a 3rd-level ranger and a pack like a 6th-level one. Dropped food distracts them 95% of the time. Sunlight and continual light hurt their eyes, imposing -1 on attack rolls, damage and Armor Class.

Wild packs are tight family groups that patrol a wide range with several burrows, ducking into the nearest before dawn; they avoid daylight whenever they can. Scent tells each hound its rank, so there is no infighting, and a weaker pack yields to a stronger one after one sniff. Packs of ten or more have a 25% chance of an exceptional leader with 5+3 Hit Dice, +2 damage and Low Intelligence (5-7). It tracks as a 9th-level ranger, as does the pack it leads, and uses simple tactics that catch adventurers and militia off guard. Females are bigger and often, though not always, lead.

Trollhounds love trolls. A troll lair housing at least four trolls has a 30% chance of 2d4 hounds standing watch by day and hunting beside their masters at night. Their only treasure is loose coins or gems in their bellies and gear dragged home on corpses.

Fearless and ravenous, they favor live prey over carrion and often see the humans of a nearby settlement as just another part of its herds. Every two or three years a female whelps one or two pups, which start with 1+1 Hit Dice and -4 to damage, run and hunt at five days, and track as adults within two weeks if they survive. Every six months they add 1+1 Hit Dice and +2 damage until reaching adult strength. At about 30 years their regeneration fails and the pack eats them. Their blood serves minor magic and potions that heal, cure or cause disease.