[RPG] How should I set up and execute air battles in the session to avoid easy encounters


I'm running the Storm King's Thunder campaign, and we are at the portion where the PCs get an airship to travel around in, the airship is about 1000ft in the air. There are approximately 5-6 lvl 7 PCs, and they have 3 or 4 hard encounters a day. There are two wizards, a warlock, ranger, paladin, blood hunter, sorcerer, and fighter.

For the most part, they have had fun with the different weapons and enemies they have faced; however, I find that one or two spellcasting PCs have been using spells such as mind sliver, polymorph, and hypnotic pattern to defeat more challenging encounters, such as one with a roc and wyvern. They make the creature make saving throws with hypnotic pattern and cause the enemy to fall to its death, and using mind sliver makes it even harder, especially on low wisdom creatures like rocs. Or with the polymorph spell, they cause the enemy to become a fish or chicken and throw it off the edge, and since the damage carries over, it kills the monster. I realize it was legal and made fights funnier, but it does get annoying when it's happening in almost every fight. Are there any suggestions on how to keep them on track without them making every encounter easy?

I thought of giving the monsters immunity to these effects, but it just sounds like a bad excuse for me not being prepared.

Best Answer

Combat balance is always tricky, and airship-related elements can make it harder. I'll try to focus on the novel environment of the airship, since that's the meat of the question. But for completeness, a few issues about combat balance generally:

  • Combat difficulty estimates (like a hard encounter, deadly encounter, etc.) are just that-- estimates. And not very precise ones. Further, the difficulty of an encounter is mostly defined around the likelihood of PC KOs. Even a deadly encounter is one that PC party is expected to win
  • Powerful parties are powerful. They have lots of options to deal with a variety of situations, and one manifestation of that is that they can approach a given encounter in many ways. Some of those ways will make certain combats pretty easy for them, such as gaining access to Polymorph. With options like that available, an encounter may need to be much harder to suit those powerful options
  • You are running a game for a pretty large party. 5 to 6 party members (and even up to 8!) gives a big edge in terms of action economy, and allows for lots of synergies between PCs (which tends to make combats easier). If you have that many PCs, you likely need to include more enemies per combat in order to keep things challenging
  • 3 to 5 hard combats per day is below the number assumed in a typical adventuring day, and consequently it's not surprising if the party overperforms

Tweaks to ordinary combat-balance issues are covered pretty well in answers to other questions, and are not quite in scope here.

Airship combat between individual characters and enemies can be tricky to balance

As you've discovered! If you can get enemies onto the deck of the ship you can have a pretty typical combat encounter, plus an obvious terrain feature that allows shoving enemies over the side to plummet to the ground.

But if you have flying enemies that menace the ship by flying around it you can start to lose terrain features and tactics that add variety and challenge to combats. For an easy example, consider cover: outside of using the body of the ship, cover is probably going to be hard to come by. This favors spellcasters and ranged fighters, who get to act like fixed turrets.

My preferred approach to combat between PCs on or in a vehicle and enemies that move around that vehicle (this includes airships, regular ships, wagons, mine carts, and so on) tend to focus on treating the vehicle as a unique environment which is a part of the fight(s):

  • A rollable table of ship-related effects is a great tool to have, and can really alter player tactics. For example, if the airship suddenly rolls to the side PCs may need DEX saves to keep their footing or risk falling prone/taking damage/pitching over the side. Rolling a d6 every round or two to impose environmental effects like that can make a combat harder without fiddling with enemy composition, as well as adding variety to combats generally
  • Flying hundreds of feet in the air offers unique opportunities and dangers. Does the airship have to fly through a thunderstorm, possibly creating a risk of lightning damage or driving winds? Can the PCs defeat the enemies and survive the harsh environment? Does the environment make certain strategies more or less attractive, by adjusting the potential risks and rewards? Can enemies weave in and out of clouds, breaking line-of-sight and attacking from unexpected angles?
  • What are the enemies' goals? If they want to kill or otherwise impede the PCs, they might as well focus on damaging the airship itself. This can change combat from an HP-reduction grind into a race against time, and can also keep enemies out of easy reach of spells and ranged attacks. If the enemies want something other than slaughter, the fight being relatively easy for the PCs may not be enough to truly "win" the combat encounter
  • Some condition exists that means things get worse until that condition is fixed. In one combat I ran, my players were in a small ship trying to escape from a massive Orcish warship, which had shot a large hauser-connected harpoon into their deck. As long as the ships stayed attached, orcs kept climbing across the rope to board the ship. The PCs had to fight the boarders and cut through the hauser or rip out the harpoon, or else the fight would (effectively) never end and they would eventually be overwhelmed

Adventure-day design is a different beast than single-encounter design

Encounter design is always an art, and designing a challenging combat is different from designing a difficult adventuring day. A combat might be tough, but with lots of resources a party might be able to prevail. An adventuring day being tough, in contrast, means more questions about whether or not it's worth spending resources right now (for an easier current combat) versus keeping something in reserve for potential future combats, and surviving those later combats when the resources are gone.

And however easily your players dispatch threats in a given fight, if they have more fights they will eventually run low on resources and face much greater danger. More combat encounters per day, with fewer opportunities for rest, lead to much greater challenges for the party.