I wanted a Mighty Deed of Arms to try to recreate a common scene in gunfights (at least on television and in movies) - both sides crouching down behind cover, popping up for a moment to return fire, before immediately ducking down again. Occasionally, someone uses this situation to try to sneak off to a flanking position and hit the other side where they're not shielded. Other times, the exchange of gunfire is covering someone's getaway.
Because guns are so deadly, and no one is really wearing effective armor, the first thing anyone in a gunfight seems to do is look for something to hide behind, and then both sides trade shots while looking for some kind of advantage or way to break the stalemate. (Often the fights seem to end when the heroes on one side manage to take down the villains on the other by hitting the bad guys right as they're emerging to let off another volley.)
So my goal here is to simulate that kind of gunfight. Both sides are hiding and unable to really hit each other until something changes. Both sides are laying down cover fire to prevent the other side from getting the upper hand. When someone is laying down effective cover, it's impossible for anyone on the other side to approach or out-flank them, unless they're very sneaky, or can find an alternate route. The only people in danger of being shot are the ones creating the cover. Cover fire is also not automatically symmetrical. If one side has more shooters, it's easier for them to control the situation. It's also possible to get out-gunned, so if one side has bigger or better guns, they're probably going to dominate the scene.
At the same time, I did try to keep the rules as simple as possible, while still allowing (and encouraging!) the above scenarios to play out. Hopefully what I've written makes intuitive sense when you think about the kind of gunfight it's meant to simulate.
I'm playing in a "weird West" themed game some weekend with Stormlord Publishing, so hopefully I'll get a chance to see how this works out in actual play. The one change I'd consider making would be that even the shooter can only be targeted by a return of cover fire (or perhaps by any Might Deed) rather than allowing them to be targeted by ordinary attacks. I'm concerned that would slow things down too much though, so I'm going to leave the opponent's options more flexible, unless playtesting shows that it doesn't work the way I hope it will as written.
Weapon-Specific Deed - Cover Fire (Firearm)
The shooter protects her allies by using her own gunfire to shield them from attack. Cover fire is typically used when the shooter and her allies are hiding behind cover, and when their enemies are in a similar position. By firing at a single opponent, the shooter can pin down her enemies to their position, prevent return fire from harming her allies, and even cover her friends retreat from the situation, allowing them to either escape or reposition themselves for the next phase of combat.
Unlike other Mighty Deeds, cover fire is not intended to hit an opponent, but to prevent them from moving by hitting close enough to them to force them to protect themselves. As a result, the shooter must hit AC 10 instead of her opponent's actual Armor Class. Larger or smaller opponents might be easier or harder to cover, respectively. Rolls of natural 20 (or other critical hits) deal damage to the target as normal.
When creating cover against an opponent without a missile weapon, the shooter receives a flat +2 bonus to her Deed Die. When attempting cover fire against an opponent who's using a firearm or other missile weapon, the shooter may receive a bonus based on the following factors:
Rate of fire: The shooter receives a +1 bonus to her Deed Die for each missile she can fire per round in excess of her opponent.
Damage die: The shooter receives a +1 bonus to her Deed Die for each 1d of damage her weapon deals in excess of her opponent.
Because the protection offered by cover fire is only effective after the shooter has attempted her Deed, she can choose to apply this bonus to her Initiative instead of her Deed Die.
An armed opponent with a superior weapon can choose either to impose a penalty on the shooter, or to receive a bonus when they return cover fire of their own.
(For example, a shooter armed with a single-shot pistol that deals 1d6 damage gets a +2 bonus to her Deed Die against an unarmed opponent, a +0 bonus against an opponent with the same weapon, and a -4 penalty against an opponent armed with a gun that fires two shots for 1d12 damage each per round. If that opponent chose to return cover fire instead, the shooter would take no penalty, but her opponent would receive a +4 bonus to their Deed Die.)
3 The shooter provides limited cover to her allies. A single targeted opponent cannot advance toward the shooter or her allies, and can make attacks only against the shooter this round.
4 The shooter provides limited cover to her allies. A single targeted opponent cannot advance toward the shooter or her allies, and can make attacks only against the shooter this round. Or, the shooter can nullify a single opponent's Cover Fire deed result of 3.
5 The shooter provides complete cover to her allies. Opponents cannot advance toward the shooter or her allies, and can make attacks only against the shooter this round. A single ally can retreat this round while retaining this protection. Or, the shooter can nullify a single opponent's Cover Fire deed result of 4 or less.
6 The shooter provides complete cover to her allies. Opponents cannot advance toward the shooter or her allies, and can make attacks only against the shooter this round. A single ally can retreat this round while retaining this protection. Or, the shooter can nullify a single opponent's Cover Fire deed result of 5 or less.
7 The shooter provides complete cover to her allies. Opponents cannot advance toward the shooter or her allies, and can make attacks only against the shooter this round. Up to two allies can retreat this round while retaining this protection. Or, the shooter can nullify any number of opponents' Cover Fire deeds whose results total at least 1 less than her Deed result. (So on a result of 7, the shooter could nullify a single result of 6, or two results of 3.)
Notes: Opponents who are not directly targeted by cover fire can still attempt to advance by using the Hide in Shadows skill, or by taking a route that leaves them out of sight behind physical cover the entire time. However, an opponent who is directly targeted by the shooter cannot advance.
The description of this deed assumes that both sides in the combat will begin exchanging cover fire from behind actual protective cover. However, at the judge's discretion, an exposed shooter may be permitted to use this deed, or an exposed opponent may be forced into retreat instead of just being blocked from advancing.
The description also assumes that the shooter will be using a firearm instead of a sling or bow. Skilled NPCs from societies that favor such weapons might be able to use them to lay down cover fire. At the judge's discretion, a player character quest for the ability to provide cover using an arrow or stone.