Wednesday, December 16, 2015

Aerial Combat!

Continuing with my Council of Wyrms conversion, I felt that a couple ancillary systems might be of benefit. This entry should be considered optional for groups that desire that level of combat simulation. I've tried to keep it fairly abstract, since there's but a small subset of gamers that care to determine mass, acceleration, lift, or wind resistance coefficients. If that's your thing, more power to you.

I took a bit of inspiration from the way some other systems do their aerial combat, so if any of it sounds familiar, that's why.

As a species with natural flight, dragons are not restricted to scrapping on the ground like common humanoids. In any situation where they have the capability to spread their wings, dragons use them to their advantage. Both players and Dungeon Masters should be aware that this adds more than the usual degree of third dimension to combat.

Of course, in the world of the Council of Wyrms, most enemies that the dragons face are more than cognizant of this advantage and plan accordingly. Every hoard or egg raiding party equips itself with ranged weapons and nets to drag the wyrms back to the ground where they can be ganged up on by pikemen and axes.

Even vassal troops are drilled in combat formations that help mitigate the aerial advantage many dragons have, such as using turtle-shell formations with tower shields to provide cover against dragon breath. Just because the Council exists does not mean there are not periodic raids and blood feuds among clans, who use their vassal troops accordingly.

A flying dragon does have risks to consider, most of which involve gravity and weather.

Action Variants

There are some actions that can be performed only while in flight. They typically follow precedents set by other actions, but have special considerations in the three dimensional battlefield that is aerial combat.


A variant of the Dash action, Dive enables a flying creature to move up to five times its flight speed, but only if the dragon loses altitude in accordance with the direction it moves. Furthermore, any class abilities that enable Dash to be used as a bonus action also apply to Dive.

For example, a young crystal dragon rogue with a fly speed of 80 enters a Dive in order to surprise a dragonslayer riding a griffon. The dragon moves up to 300 feet toward the target, but loses a similar amount of altitude.

I left the language of this open in case I decide to add more action variants for aerial combatants. 

Conditions and Flight

All dragons must be able to spread their wings and beat them unhindered to remain aloft. While players and Dungeon Masters should not concern themselves with the minutia and math behind mass, lift, and minimum speed to avoid stalling, a few guidelines help simulate these conditions.

Firstly, a dragon must have a sufficient quantity of air beneath it to take off and remain flying. If a spell or other effect (such as a bizarre trip to an extraplanar realm) removes the air from a given space, a dragon cannot fly.

Furthermore, a dragon must have enough space to keep its wings moving. Should the space around a dragon ever become insufficient, such as needing to squeeze through a place that is narrower than its base, it cannot remain aloft and will begin to fall if they end their turn in the space and are not holding onto a surface or protrusion of some kind. For example, if a Large copper dragon (10’ by 10’ space) is forced to fly through a very narrow bend in a canyon (a 5’ space), it will not be able to fly if it ends its turn within the narrow area without grabbing onto something. If the dragon cannot grab hold of something, it falls immediately.

In a circumstance that causes the dragon to lose control of its wings, it will begin to fall. Conditions that create this situation include the paralyzed, petrified, prone, and restrained conditions. If the condition ends before the dragon hits the ground (assuming they’re particularly high in the air), the dragon can catch itself and prevent a devastating crash on its turn so long as it can use its fly speed.

In the event that a dragon (or any other creature, for that matter) enters a free fall, they will plummet 600 feet per round on its turn while the condition is in effect. For example, a blue dragon is soaring 400 feet above the desert when it is attacked by a brass dragon wizard (deviously under the effects of an invisibility spell). The brass dragon banks close and casts the hold monster spell on the blue dragon, which fails its saving throw. On the blue dragon’s turn, all it can do is fall, and it hits the ground at full speed suffering maximum falling damage (20d6, for falling 200 or more feet). Ouch.

In the same example, if the blue dragon is instead at 1000 feet, it falls only 600 feet on its turn, and at the end of the same turn succeeds on its saving throw to break the hold monster effect. The dragon is no longer falling, and does not suffer falling damage when its turn comes around again (though it is only 400 feet above the ground now, at risk of being affected a second time).

This is, of course, an abstraction that only roughly considers acceleration by gravity in an Earth-like environment, but is consistent with similar abstractions from previous editions as well as prevents players from needing to determine mass, acceleration, and terminal velocity based on how big their dragon character is according to their sheet.

It is worth noting a special case scenario for the grappled condition, where both the grappler and their victim are in a clinch and fall together. In such situations, falling is done on the victim’s turn, and not on the grapple initiator’s turn.

High Winds

Flying creatures have a harder time negotiating the skies when subject to inclement weather, but the larger the beast, the less difficulty it suffers when battling against such conditions.

A Small or smaller flyer treats all flight-based movement as difficult terrain in conditions where the wind is in excess of 30 miles per hour (or 48 kph). Medium and Large flyers have a threshold of 50 mph (80 kph), with Huge and Gargantuan being unaffected up to 75 mph (120 kph). Certain creatures, such as djinn and air elementals, are not subject to the effects of high winds due to their nature as extraplanar creatures from the Plane of Air.

No flyer can engage in movement of any kind in conditions in excess of twice its threshold, becoming subject to the violent gales and possibly entering a free fall.

Minimum Flight Speed

An optional rule that some Dungeon Masters may want to use involves maintaining a minimum speed to avoid losing altitude. Dragons are huge, heavy creatures and despite their wingspan, they must maintain a forward momentum to avoid stalling.

If your DM uses this rule, you must move at least half of your flight speed each turn to maintain your altitude. On any turn which you fall to move this speed, you must succeed on a Strength (Athletics) check or begin to fall. The DC for this check is contingent on your age; 10 for wyrmling, 15 for young, 20 for adult, and 25 for ancient. The older a dragon is, the harder it becomes to remain aloft without forward momentum due to its mass.

But Wait, There's More!

I'm working on more stuff on my lair building rules, but they're seeing more an excuse to add simulationism for its own sake. I'm not terribly happy with them yet, so I'll probably break off to do another topic for an entry or two before coming back to it. When it's all done, I'll wrap it up into a handy PDF for download.

Till then!

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