By Alan McCoy from Dungeons & Dragons: Fundamentals
How to build challenging encounters against a Mastiff
Note: This has been prepared utilizing only the 5E Core Rules. The Mastiff can be found in the Monster Manual page 332. While the entry is specifically talking about the Mastiff, it can serve as the template for other dog breeds with a little creativity.
As a common part of the real world, the dog is often overlooked when attempting to determine the “in game” aspects of these beasts. While dog is considered man’s best friend, there are many other races that find them useful. Some of mankind’s enemies also find these beasts to be easily trained and loyal servants, even when not treated well.
One of the most common means of adding protection to a residence or lair, or for that matter, providing for personal protection is the Dog. Guard and Attack dogs can be taught to disarm, knock prone, and to immobilize their targets.
Dogs are often used in hunting packs as well, utilizing their superior senses of smell and hearing to assist their masters in finding their prey. These skills often include chasing and otherwise immobilizing their prey until the master arrives.
Dogs can be trained to detect and react to many significant smells, these can be specific monsters, the spices commonly used by an enemy nation for cooking, weapon oils, specific foods or even poisons.
Dogs can be trained to guard and to help herd many types of farm animal as well.
Dogs can be trained as beasts of burden and are sometimes used as mounts by small stature humanoids such as Halflings and Gnomes.
Step 1) Let’s Review what we know about the Mastiff:
Mastiffs are medium beasts with no alignment in and of themselves, they essentially gain a pseudo-alignment by emulating the behavior of their masters.
Mastiffs are fast on their feet, travelling 40 feet per round.
Mastiffs are Strong (+1), Nimble (+2), and Hearty (+1). Mentally they have rather high intelligence for an animal (-4) but rapidly learn from their mistakes (+1). Their body language and manner help them communicate their feelings (-2).
Mastiffs are naturally highly aware of their environment (Perception +3), and gain advantage on any checks using their sense of hearing or smell. (Keen Hearing and Keen Smell).
Mastiffs are beasts, and thus speak no languages, but they can be taught to recognize and respond to commands given in a language they have been trained to understand.
Step 2) Determine the probable Strategy.
As a trained animal, the Mastiff has no strategy of its own, it does what its master directs, be it guard this patch of ground, sniff out poisons at the city gate or herd the sheep.
When left to their own devices, the Mastiff has two major drives, find food, and find a mate.
Step 3) Determine Tactics
The primary weapon of the Mastiff is to bite and attempt to overbear the target.
Additionally, remembering that “monsters” have the same action inventory that characters do:
Trip: by lunging at the pit of the knee. As a DM I’d give the target a DC 12 Dexterity Save or be knocked Prone.
Help: An Attack Dog or War Dog can Help their master by distracting the target.
Interpose: A dog can be taught to get between a target and its master, this essentially gives the master “Cover”, by forcing distance, and can result in “Cover” increasing that AC of the Master.
Intimidate: Dashing after a target, barking and growling, they can cause some targets to flee in fear.
Step 4) DM Tips and Observations
The base Armor Class of the Mastiff seems low at 12, but I would leave it alone, these are beasts that a normal everyday person (a non-adventurer) could encounter. It is possible to purchase armor (called barding) for a dog that has been trained to wear it. War Dogs and Guard Dogs, perhaps a Dog Mount.
I would provide Guard Dogs and War Dogs with proficiency in the Intimidation Skill.
Dogs will usually ignore commands given by a voice that they do not recognize, however, to avoid confusion, especially with magical means available to emulate the voice of their master, many dogs are taught to accept commands in strange, ancient or unusual languages not normally known in the area. (Example: I knew a trained her guard dogs to obey only commands given in Japanese).
The bite/overbear primary attack for a Mastiff: Bite damage is okay, though I’d prefer a Strength of 14 and a +2 modifier. The overbear DC at 11 is, in my opinion too low. I’d go with a 12.
As mentioned before, this entry can be used as a base template to reproduce and emulate many breeds of Dog. Enjoy this. Get your players to participate in the process. Variety is after all, good for the game.