Dragon Encounters

Making dnd combat fun, finding monsters that fit together, monster tactics and strategies, and other ways of using the monsters of dungeons and dragons

ANCIENT BLACK DRAGON: Fighting is the Ruins


Combat rating 23


1 Ancient black dragon (CR 21)

1-2 Oni (CR 7)

1 Death slaad (CR 10)

3-4 Shambling mounds (CR 5)


Combat rating 24


1 Ancient black dragon (CR 21)

4 Bone devils (CR 9)

1 Hydra (CR 8)


Combat rating 27


1 Ancient black dragon (CR 21)

2 Young red shadow dragons (CR 10)

3-4 Fomorians (CR 8)

1 Lich (CR 21)


Combat rating 28


1 Ancient black dragon (CR 21)

4 Goristros (CR 17)

3 Hezrous (CR 8)


The Monster Manual tells us that black dragons make their lairs on the ruins of empires. I’m going to utilize this to turn the ancient black dragon’s lair into a veritable nightmare for any aspiring adventurers.

Combat encounter 1 (difficulty 23)

Arrange the dragon’s lair as a series of islands or platforms above the swamp water, high enough to look impressive but not high enough to prevent the dragon from using the lair action where the waters rise up and pull the PCs down.

You can also set the combat in the ruins of a castle, with crumbling walls breaking up the battlefield, although this will hamper your ability to use this lair action. Possible you can place pools of stagnant water in the corners of some rooms, or a former well or decorative pool with its stone rim completely gone, leaving just a deep hole full of water.

To make this combat lethal, there are various traps set up around the area. Choose 1-2 of the following types, or make up your own: Pillars that sprout blades that whirl around the pillar before retracting, openings in the wall or engravings in the wall that shoot flames or darts, spikes that emerge from walls or the floor, and/or large weights that fall from the walls or off of trees when the PCs are under them.

The above traps all do damage. While nasty, they’re far less bad than traps that affect movement. I would suggest using mostly damage traps, and perhaps a few of the following types: Nets that fall and entangle them, trapdoors opening under their feet, tripwires or slippery floor causing them to fall into the swamp, and/or rope traps that hoist them off their feet.

The triggers for these traps are tripwires, or levers in the ground. Basically, they’re all but unavoidable, because while the rogue can probably find them with perception checks, you’re not going to have time to do that while fighting an ancient dragon. At most, they can tell which areas are likely to contain traps (such as in front of the engravings, or next to the pillars) but they shouldn’t be able to find the triggers directly.

(Giving them some hint of where the traps are likely to be triggered from is one reason I suggested limiting it to 2-3 types of traps, total. The other is to make it more thematic.)

I would also advise small walls, large pillars and statues, and/or large bushes or low hanging trees to set up blocks on line-of-sight around the battlefield. This will force the ranged PCs to keep moving. Otherwise, only the melee will be affected.

The dragon will know all the triggers, (it’s lived here for years, possibly centuries) and will move around sneering at them without worrying about triggering traps. On its turn, if it can use its breath weapon to attack from a distance, it will obviously do so. If the breath weapon is on a recharge, it can move in and out of range, accepting an attack of opportunity as the cost of attacking. Either that, or move out of range after the first PC takes their turn, using the wing attack legendary action to hopefully avoid any opportunity attacks.

Another thing it can do would be to ready an action, perhaps to attack the first time it’s in range of a PC. (Unlike with the extra attack that many PCs get, nothing about multi-attack suggests that it has to happen on your turn.) Normally, this runs the risk that the other side won’t move into range, and that your turn will be wasted. The dragon, however, can move in-between PC turns by using its wing attack legendary action. As such, there is virtually no chance that it won’t be in range for a full round.

(This will cost it in terms of legendary actions, which is why the idea of moving in and out of range on its turn is also tempting. That, and because springing this on your players mid-battle [as opposed to right away] seems fun.)

The dragon’s wing attack also means you don’t have to worry too much about it getting pinned in place if they manage to surround it.

The last thing to note is that the dragon might also choose to use some of its attacks on the scenery, to knock walls down into heaps of rubble that will restrict movement, to take down bridges, and to make holes in the floor. The best place to do this is where it will separate PCs from each other. By doing this through attacks, it can avoid having it take its full turn. It will only cost it one of its attacks.

(I would bring the existence of the siege monster trait as proof that attacking a building is possible. Not that the dragon has this trait, just that this trait proves that attacks on buildings are a form of attack.)

(With lower tiers, I would be reluctant to place traps that they have no good way to find. Once we reach CR 20, I feel that there is no reason to hold back. At these levels, players are nearly invincible, and my main fear is that I’m not making it nearly deadly enough.)

Combat encounter 2: The ruined tower (difficulty 23)

(You can use this as its own encounter, or you can use this before or after the first combat encounter. Personally, I like that idea better. I feel that boss fights should have a second stage. You will have to make sure the dragon doesn’t take too much damage in the first stage to allow a second stage, though.)

There is a tower at a corner of the dragon’s lair, and the dragon lures them into it. One way it might do this is by rigging a collapsable floor, probably a wide one, and setting it up so that they can only shoot at it if they step into the courtyard. (So as to get all the PCs.) It can trigger the floor’s collapse by hitting it with its claw or tail in the right place, or it can achieve it through its wing attack, which will also knock the PCs down.

You can also have the PCs trigger it with one of their spells doing too much destruction, or by stepping in the wrong place. Either way, they find themselves sliding down on a pile of rubble. They get swept through the door of the tower, and the rubble closes up the entrance behind them.

The other way to get them in would be to have the dragon fly in. When they follow it, they step on a tripwire that triggers the landslide. The dragon could theoretically escape by flying, although the walls might be too narrow to allow that. A better way would be to have the dragon swim out through the pool that is at the bottom of the tower. (See description below.)

To stop the players from following the dragon out, you can have the waters be too muddy, so that if they try, they’ll get stuck in the mud. (The dragon has longer legs, and the strength to churn through the mud.) You could also have the dragon block the way out behind it, possibly by attacking and collapsing the wall. If you make the waters be acid, then the reason the dragon can go through them and the PCs can’t is obvious. Regardless, you end up with the PCs stuck in the tower and the dragon above.

Tower description: The tower is in total ruins. The roof is gone, leaving the top of the tower open to the sky above. The staircases leading up and any upper floors are all gone, with only a few jutting out stones from the walls giving any hint that they once existed. Even the floor is collapsing, with a huge piece missing in the middle, and muddy water spilling out of it, coming up from the swamp below. What’s left of the floor is unstable, and feels like it might collapse soon as well.

(Alternatively, have the “Water” be hissing acid, the dragon having long since turned the tower’s basement into its personal trap and acid bath.)

The dragon, on reaching the top* will spend its turns belittling them, threatening them, and its actions (when it doesn’t have its breath weapon) tossing down heavy stones. Apart from the damage the stones do it and when they hit them, they will also be eroding the floor’s remaining strength. After 2-3 rounds, you’ll want to narrate the floor beginning to collapse, and have pieces of it go each turn after that, at an increasing rate. Eventually, they’ll be holding onto the walls.

With its first lair action after the PCs land in the trap, have it fill the inside of the tower with biting bugs. On the next turn, it will use the water to try to pull them in. (If you’re not using acid, consider filling it with biting fish. I.E swarms of quippers.) Using darkness might be a mistake in this encounter, as it will also prevent the dragon from seeing them, so on the third turn you can move the insect swarm a miniscule amount and thereby recharge the water action.

With its legendary actions, it can use its wing attack anytime they try to climb the wall, and its tail attack to target individuals who make their save against the wing attack. While the tail attack doesn’t normally knock them down, I would think that taking a tail attack while climbing should have a real chance of doing so. (Fear would also be a powerful tool here, if it still has it. However, that is an if. I’m somewhat inclined to say the black dragons use up their fear ability right away, in order to impress/intimidate the PCs.)

* Have the dragon dash to get there as soon as possible. Not that you should let the players know that it dashed, that doesn’t fit the majestic image that a dragon should have. Just narrate that it reached the top and is now above them.

The way dungeons and dragons games often end up working, one or two of them might escape getting trapped in the tower. Still, the dragon will be high up, which they’ll be climbing the outside of the tower to reach it, and it might be able to knock them down. If this doesn’t work, then I’m afraid you’ll have to adapt. I can’t possibly plan for you everything the dragon might do, nice as it would be to be able to do that.

The inside of a ruined tower, with the floor being bare earth with a muddy pool at the side, and the top being open to the sky. A black dragon is visible above the top of the tower

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About Me

I have been a DM for several years, and I was designing home RPG games since my young childhood. I have been a fan of many different types of games (computer, board, RPG, and more) and have designed several for my own entertainment. This is my first attempt to produce game content for a wider audience.