Variant: Shared Turn Combat 1.1

Welcome to the rules for the Shared Turn Combat variant. Written for the 5th Edition of Dungeons & Dragons, this system offers an alternative set of rules to approaching combat from the standard rules provided on pages 189 and on in the official Player's Handbook.

The context

There are three widely known systems to approach combat in 5E: the regular rules, which will henceforth be referred to as the 'Basic Combat system', are the most common. Then there is the Greyhawk Initiative System, which was introduced as an alternative to Basic Combat by Wizards of the Coasts themselves. Finally, there is the somewhat rare Popcorn Initiative, which was originally devised for older editions of the game and popularized by the Angry DM, a well known DnD blog.

Introduction

Though all three of the above systems have advantages of their own, they all suffer from one notable disadvantage that none of them really addressed: because the system is turn-based, the narrative suffers.

Consider this hypothetical scenario: a party of four player characters, including a wizard and a paladin, are standing in a line, next to each other. A furious Ogre runs at the group's wizard with the aim to knock them down. The wizard has some reactions available to them - such as the Shield spell - and one or two feats may allow for a single attack of opportunity, but the default implication is that the entire party stands there while the Ogre crosses 40 feet of distance, swings his club at the wizard, and potentially knocks them out. If an Orc Archer happens to be next in the initiative order, they may be able to launch an arrow or two at the Wizard and potentially even cause them to die at the start of their turn.

In a more realistic scenario, a number of things might have prevented this scenario. For example, the wizard could have tried to cast Ray of Frost to slow the Ogre down to prevent it from reaching him. Or he could have anticipated the clearly incoming blow and attemped to dodge it. Or the battle-hardened paladin might have jumped in: whether by taunting the Ogre in an attempt to get it to attack him instead, by attempting to block it's path, or by healing the wizard after the first blow lands.

While, in the earlier mentioned systems, 'the moment at which you take your turn' is meant to determine whether any of the above scenarios can take place ("are you quick enough to...?"), the case stands that combat can end up feeling sluggish and more strategic than the chaotic, moment-to-moment upheaval it may realistically be. Even the best of DMs, who can flow like a dolphin, might suffer from this issue due to the simple fact that 5E's combat is set up like a tabletop wargame.

Though it is perhaps impossible to fully fix this issue without getting rid of turns altogether - and thus turning fights into shouting matches over who goes first - the Shared Turn Variant introduces a set of new mechanics that attempt to alleviate the above issue and make combat flow in a way that is more in tune with the narrative.

Shared Turn Combat

At its core, Shared Turn Combat follows most of the rules of the Basic Combat system. There are, however, some key changes that alter the dynamic of a fight. A round during Shared Turn Combat proceeds as follows:

1. All combatants roll initiative.
2. Whenever a character's turn is up in the initiative order, they can choose to declare themselves the Actor (A) for this turn by briefly and clearly stating the plan they want to follow.
   • Example declarations: "Muttering some incantations, I aim a Firebolt at the Goblin chief" for a player, or "the Ogre charges at Leomund the Wizard, wildly swinging his club" for the DM.
   • Movement and actions declared this way must be followed to a reasonable degree during the turn. In case of doubt, what is considered 'reasonable' is up to the Dungeon Master.
   • Any character that is afflicted by a spell or effect that forces them to make a saving throw on their turn automatically becomes an Actor.
   • If a character chooses not to become an Actor, the impetus simply moves on to the next creature in the list.
3. After an Actor has been declared, any character in the initiative list may, in the same way, use their reaction to declare themselves a Reactor (R), provided they are not incapacitated or surprised.
   • Example declarations: "Seeing the Firebolt coming right at him, the Goblin Chief attempts to dodge it by jumping behind a crate" for the DM, or "Seeing the Ogre running at me, I mentally prepare to Misty Step away once he reaches me so I can hit him in the back with my Ray of Frost" for a player.
4. If no Reactors are declared, the Actor takes their turn as they would in the Basic Combat system. In any other case, however, both the Actor and any Reactors perform a shared turn, during which they all get to act. Either way, at the end of a turn, all characters that were just Actors or Reactors are removed from the initiative tracker.
5. As soon as the initiative tracker is empty, the round is over and the process begins again from step 1. Should initiative reach 0, all characters still remaining in the list lose their turn.

The 'Shared Turn Priority List'

Whenever a shared turn occurs, each character involved gets to use movement, an action, a bonus action, and an object interaction. Listed below is the order in which each of their activities are prioritized. Note that the list contains priorities only, and that characters aren't forced to take a specified action on the step it is described at. The list merely ensures that, in case of conflict, one activity occurs before the other.

1. (R) Dodge action
2. (A) All spellcasting
3. Alternating ranged attacks or cantrip casts, starting with (A) and ending when all combatants run out
4. (A) Basic (non-dash) movement
5. (R) If no hostile targets are in melee attack range of (R): Spell casting or any action not mentioned in this list
6. (A) Any remaining movement
7. (R) Basic (non-dash) movement
8. Alternating melee attacks, starting with (A) and ending when all combatants run out
9. (R) If step 5 was skipped: Spell casting or any action not mentioned in this list
10. (R) Any remaining movement

Usable at any moment between steps or attacks:

• Both: Bonus actions & Object interactions
• Both: Any 'extra actions' such as those granted by the Haste spell or the Action Surge ability.
• (A) only: Any type of action that is not mentioned in the list.

Reactions function as normal for all combatants, and Reactors go in the order their turns were declared.

Five Additional Rules

1. Effects caused by bonus actions and object interactions are resolved instantly. For example, as a Reactor, it is possible to use the Misty Step spell to teleport away from an enemy right before they would otherwise attempt to hit you with a melee attack during a shared turn, and after they have already used their movement to get within melee range of you.
2. Similarly, spell effects that can be resolved immediately, are resolved immediately, though a target may never make two saving throws for the same spell in one shared turn. For example: if an Ogre (A) is using dash to reach you (R), successfully casting the Fear spell on them as part of step 5 forces them to abandon whatever plans they had for the turn and instead spend the remainder of their movement running away from you. The Ogre does not make a second Wisdom saving throw, even if it breaks line of sight of you, and is thus affected by the spell for at least one more turn.
3. Any Reactor who casts a spell of 1st level or higher as part of step 9 makes concentration checks for every individual instance of damage that affected them during the shared turn, as if they were focusing on a spell. On a fail, the spell they were trying to cast is ruled as 'interrupted while casting', meaning its effects do not take place but the spell slot is nevertheless expended.
4. Any mechanic that magically compels a target to take certain actions - such as the Suggestion or Fear spells - forces that target to become an Actor or Reactor whenever doing so would allow them to carry out said action.
5. Finally, abilities that have an effect that lasts until the start of the caster's next turn must always have an opportunity to trigger before that moment. Whenever one does not, it lasts until the end of the target's next turn instead. For example, If a Wizard acting on initiative count 1 casts Booming Blade on an Orc and then becomes a Reactor on initiative count 25 in the next round, the Orc will still be susceptible to Booming Blade's 'damage upon moving' component at initiative count 16, despite the spell's description stating that it would end at the start of the Wizard's turn this round.

Examples

Below are a few sample scenario's to illustrate how the system plays out in the game itself.

Example 1 - The rogue and the hag (a simple scenario)

Gereneth the Wood Elven rogue and Johnston the Human Paladin are fighting a Green Hag which is 60 feet away, and neither party is surprised. Gereneth has rolled a 21 for initiative, the Hag a 16, and Johnston an unlucky 5.

Gereneth gets the first opportunity to do something in the fight, and he names himself the Actor by describing "Daggers drawn, I dash towards the Hag, aiming to stab her in the back. Upon hearing this, the DM states "Seeing Gereneth approach, the Green Hag takes a firm combat stance and bares her claws", declaring the Hag as the Reactor.

Since neither party takes the dodge action (1), casts any spells or makes any ranged attacks (2+3), Gereneth uses his basic 35 feet movement to run towards the Hag (4), ending up a good 20 feet short of being in melee range. He then uses the Rogue's 'Cunning Action' class feature to use dash as a bonus action.

The Hag did not indicate she wanted to cast a spell (5), and as such Gereneth immediately gets to use his additional movement in order to reach her (6). Since the Hag is not moving (7), he also gets to make his attack (8). After Gereneth's strike, the Hag retaliates by making her own Claw attack (8).

Though she hits, she realizes she was hurt quite badly by Gereneth's dagger and decides to use her remaining movement to run away from him (10). Doing so does provoke an attack of opportunity by Gereneth, which he hits. Both Gereneth and the hag have now used their reaction.

At this point, the shared turn has passed and both Gereneth and the Hag get removed from the initiative tracker. This leaves a lone Johnston, who gets to take his turn as normal, with the Green Hag being unable to react. Afterwards, all three combatants reroll initiative for the next round.

Example 2 - The Rogue and the Hag (another simple scenario)

In a parellel universe, Garanath the Wood Elven rogue and Jahnstan the Human Paladin are fighting a more cunning Green Hag that is 30 feet away. Neither party is surprised, Garanath rolls a 21 for initiative, the Hag gets 16, and Jahnstan is still stuck with his unlucky 5.

Garanath declares himself the Actor of the first turn in the fight by stating "Daggers drawn, I run towards the Hag, aiming to stab her in the back". Upon hearing this, the crafty DM states that "Seeing Garanath approach, the Green Hag yells something foul at him and begins backing out".

Once more, neither party dodges (1), and Garanath does not use any spells (2). This time, however, the Green Hag shouts "Your mother was a hamster and your father smelled of elderberries!" at the Elf, insulting him with the Vicious Mockery cantrip as he approaches. Garanath fails the Wisdom saving throw associated with the spell and takes psychic damage (3).

Immediately afterwards, Garanath arrives at the Hag (4), this time not having to use dash to get in melee range. Before he gets a chance to attack her, however, the Hag uses her own basic movement to run away from Garanath (7), provoking an attack of opportunity from him. This attack misses because of the disadvantage caused by the Vicious Mockery cantrip, which now ends. Not wanting to miss out on his attack but keeping in line with his original declaration, Garanath now decides to use dash as a bonus action and immediately run after the witch (6), causing him to be in range again, and allowing him to make his initially planned attack (8). The shared turn now ends, and Jahnstan gets to act.

Example 3 - The Troll Cave               (an average scenario)

A party of level 5 characters - Lorka the Barbarian, Haldern the Fighter, Vallas the Sorcerer, and Esthelle the Ranger - stands eye to eye with three vile Trolls inside of their cave. Vallas topped the initiative rolls at 17, Lorka rolled a 16, the Trolls all sit at 15, Haldern got 9 and Esthelle 6.

Vallas declares himself the first Actor by describing how he targets the front-most Troll with a Fire Bolt. The Troll in turn becomes the first Reactor as the DM states that it'll take the dodge action in an attempt to move out of the way. As the Actor, Vallas' Fire Bolt goes off immediately after the dodge (1), and manages to hit the Troll despite him having disadvantage on the attack roll (2). Since it just dodged, the Troll cannot perform any other actions (3). Vallas decides to take a step back, just in case (4). The Troll, not knowing any spells (5), then angrily charges forward at the party (7), but finds its way blocked by Haldern and Lorka, who form the party's front line. Since nobody dashed, the Troll has expended its action, and all spellcasting has already finished (8, 9) this is where the shared turn ends - but not before Vallas decides to spend his bonus action turning two of his Sorcery Points into a 1st level spell slot.

Lorka now sees an opening, and, sitting at initiative 16, she declares herself the next Actor by shouting a powerful warcry while rushing behind the lone Troll, aiming to attack it from behind. Upon doing so, both other Trolls declare themselves as the Reactors as they aim to surround and attack Lorka while her attention is on the first Troll.

This time, nobody dodges, uses a spell, or fires a ranged attack (1, 2, 3), so Lorka immediately maneuvres behind the Troll that is now close to the party, and she rages as a bonus action (4). With no spells being cast (5) and Lorka being in position (6), the two Trolls in the back move in and surround a firmly planted Barbarian (7), who throws her first strike at the flanked Troll (8). Immediately afterwards, both of the reacting Trolls attempt to Claw at her once in return (8). Lorka then gets her secondary attack, again aimed at the flanked Troll (8). With both her attacks down, the two other Trolls each use their Claw attack once more, followed by their Bite attacks (8). Despite the onslaught the Trolls unleashed, Lorka survives due to her Barbarian rage. With nobody dashing or casting spells (9, 10), the second shared turn of the round ends.

Finally, with Vallas, Lorka, and all three Trolls having acted, Haldern and Esthelle get to take their own uncontested turns. They use these to finish off the flanked Troll, now that it is no longer able to react.

Example 4 - Battle at the shrine     (a complex scenario)

After exploring a set of seemingly abandoned ruins, Bolbus the Halfling Bard, Komli the Dwarven Paladin and Terrinius the Human Cleric are surprised to find themselves surrounded by two Robed Cultists, one Dark Champion brandishing a two-handed sword, and a raging Barlgura demon. The Champion calls out to the party, giving them a chance to join the dark side before resorting to violence. The party politely declines, and initiative is rolled.

Both Komli and Terrinius roll high and end up above 20 initiative. The Dark Champion gets 19, the Barlgura 15, the Robed Cultists 12 and Bolbus ends up last with a meager 11. Though Komli and Terrinius have the opportunity to become Actors first, they are both afraid of leaving their defensive position and decide to pass, preferring to react to what the cultists do.

As such, the Dark Champion becomes the first Actor with the DM declaring "the Dark Champion raises his zweihander, shouts out 'get the weak one first!', and dashes at Bolbus with uncanny speed". Eager to defend their unarmored companion, both Komli and Terrinius declare themselves as Reactors. Komli by stating "seeing the Dark Champion approach, I cast Compelled Duel in an attempt to distract it from Bolbus as I try to step in between the two and ready my Warhammer", and Terrinius by stating "I start casting Bless on all three of us".

In this situation, no Reactor uses dodge, the Dark Champion does not cast any spells, nor does he make any ranged attacks, and neither Komli nor Terrinius use a regular cantrip or a ranged attack of their own (1, 2, 3). The Dark Champion, who is 50 feet away and has only 30 feet movement, uses Dash as a bonus action (one of his traits) to ensure he has the movement to actually reach Bolbus. He first uses his base 30 feet to move closer (4). Since Compelled Duel is a bonus action, Komli decides to use it as soon as the Dark Champion comes within range, and he immediately fails his save.

Since the Dark Champion is not currently in melee attack range of Terrinius, he tries to cast Bless on all three of our heroes (5). However, one of the Robed Cultists uses their reaction to Counterspell him, and the spell has no effect. At this point, the situation has changed in such a significant way that Dark Champion has a choice: either aim his attacks at Komli, who has now challenged him, or use his additional movement to reach Bolbus (6). To press the point, Komli uses his own basic movement to move up towards the Dark Champion (7).

The DM decides that this champion is particularly arrogant and chooses to attack Komli, who then strikes him back in return (8). Realizing Komli's Compelled Duel has been effective, Terrinius quickly uses his bonus action to cast Shield of Faith on Komli, who then dodges the champion's second attack. The Dwarf hits with his own second attack, and the Dark Champion ends the skirmish by throwing his third and final attack at Komli (8).

With Komli, Terrinius and the Dark Champion out of the initiative order, the Barlgura, both Robed Cultists, and Bolbus are left. The Barlgura, who is up next and 20 feet away from Bolbus, is declared an Actor by the DM: "With a thunderous roar, the demon takes a leap towards Bolbus, aiming to smash the puny Halfling". Bolbus declares himself the Reactor by stating "I try to hold my ground, and start casting Fear as the Barlgura approaches".

Bolbus does not dodge (1), though he does immediately stow the lute he used for inspiration before the fight broke out, freeing up his hands for spellcasting. The Barlgura does not cast any spells (2), and no ranged attacks are made, nor are any Cantrips cast (3). As Bolbus begins casting his Fear spell, the Barlgura lands in front of him (4). Since it is now in melee range, Bolbus does not get his spell off (5) before it starts attacking (8).

Thanks to a set of unlucky dice, the Barlgura only hits one of its attacks, prompting a concentration check from Bolbus to see if his Fear succesfully goes off (9). As he passes the check, the Barlgura is affected by the Fear spell, and fails its save. This means it has to spend the remaining 10 feet of movement it has left running away from Bolbus, granting him some space. Additionally, the Barlgura will be forced to become an Actor or Reactor as soon as possible during the next round, at which point it will be subjected to Fear's effects, and forced to Dash and run away from Bolbus - assuming the Bard has not lost concentration on the spell by then.

Cheat Sheet

Start of a round: roll initiative
 
When you are up, either:

1. Pass
2. Name yourself the Actor by declaring your intentions for the turn

 
When a character becomes Actor:

• If you have not had a turn yet, use your reaction to name yourself a Reactor by declaring your intentions for the turn

If no Reactor is declared, the Actor's turn occurs as normal. Otherwise, follow this order:

Actor: Take bonus and class actions after any act

Reactor: Take bonus actions after any act  

• Resolve any spell effects during the turn if possible
• Use reactions as you normally would, though note that Reactors cannot use any

Credits

Made by /u/Mozared in the Homebrewery. Thanks to Maity, RikG & Aran for their feedback.

Art: Archer by TheGryph and Paladin vs. Demon by Paulo Puggioni.