By Alan McCoy from Dungeons & Dragons: Fundamentals
How to build a challenging encounter against Goblins
Note: This has been prepared utilizing only the 5E Core Rules. Goblin Leaders with a Character Class would of course make for an even tougher encounter.
Goblins are often considered mere cannon fodder, useful for a few low level encounters, at least until the Player Characters are able to handle something stronger, then they are often forgotten about.
This view is a mistake. Goblins played properly can be a horribly nasty encounter.
Step 1) Let’s review what we know about the Goblin
Armed with Scimitar or a Short bow, they typically use Leather armor and Shields. Darkvision. High Dex, Low Strength. Average Intelligence. Special Ability: Nimble Escape which allows them to Hide or disengage as a bonus action. Very skilled in Stealth. Found in Forests, Grasslands, Hills and the Underdark.
Step 2) Determine the probable Strategy
The center of the goblin strategy is the Ambush.
Ambush almost always relies on attacks from Range, so whenever possible, the goblin will attack using their short bows from hiding.
The Goblins will outnumber the party members since they will not launch the ambush unless they feel they have the advantage.
Step 3) Determine Tactics
The Goblin will attack from Stealth: (Advantage from Hiding).
The goblins want enough Range so that no PC can get to them in a single round, yet still close enough so that their short bows will still be effective (80-foot max). Roughly 40 feet away is about as close as they want to get.
Because Goblins are a SMALL class creature, a goblin has a good chance of successfully hiding behind a fallen log or a tree, even if it fails, it will enjoy 75% cover (+5 AC).
Hit or Miss, because the attack gives their position away, they will immediately hide and stealth move to a new location. A Goblin must end it’s turn HIDDEN or it will be vulnerable, so the ATTACK/HIDE/MOVE order of action is very important.
If the Goblins can stay at range, rinse and repeat.
Goblins want to provoke the PCs into splitting up. Giving Chase and allowing them to focus fire ONE PC until they are dead-dead-dead.
Should a PC get to melee range however, Disengage, Dash out of reach, find cover and hide as soon as possible. This will force a PC to use their action to DASH to keep up.
If the PCs take cover themselves, the Goblins will break off and set up another ambush farther down the trail.
What about Melee?
Goblins know that they are physically weak, so the only time they will willingly engage in melee attacks is when they believe they have overwhelming advantage. At least 3:1, preferably 4:1 or more.
Each Goblin will either Dodge, Help or Attack. (I roll randomly for each goblin as they aren’t wise enough to be coordinated in their tactics… and because they are cowardly, they tend to Dodge a bit more. so d4 Dodge, Dodge, Help, attack.
Dodging Goblins are attacked with disadvantage.
Helping Goblins give advantage to attacking Goblins.
Okay, so what about Lairs?
Goblins recognize the value of alarms and traps, and they’re not about to let anyone get the drop on them. Their traps are generally crude and designed to create a lot of noise. Deadfalls, snares, staked pits are all within their grasp.
Additionally, Goblins are pretty good at concealing their lairs.
So, what about Goblin weaknesses:
Goblins are Squishy and they know it. They are cowardly and will run away easily.
Goblins are greedy. If they defeat an opponent, and no other opponent is obvious, they’ll loot the body immediately, even if the fight is still going on.