*System Splicing is a series looking to break down tabletop RPGs into mechanics you can apply to other games.  Splicing is about focusing on add-on mechanics rather than entire systems.  These mechanics can set the tone, support the system, and improve your experience, but are not imperative to play.  Through this series, you should be able to one day splice them all together into some sort of wonderfully horrific frankensystem.

System splicing at its finest.

Or, Aviv, and Eran Aviram. “Time to Get Role-Ing.” Up to 4 Players, 2 July 2015.

D&D 5th ed.

In geek spaces it’s near impossible to talk about tabletop RPGs without someone mentioning 5e, Critical Role, or the plethora of other 5e actual-play podcasts.  So before we get to dissecting the odd and esoteric, let’s talk about the monolith in the room.  D&D 5th, originally called D&D Next, is the latest installment for the most culturally referenced tabletop RPG in existence.  Prior to the majorly popular Critical Role, Dungeons & Dragons has been referenced in Community, Big Bang Theory, Stranger Things, and more.  It’s currently a d20 attrition-based system with a strong emphasis on medium-to-high fantasy heroics.

What makes the system stand out from its previous iterations is its ease of play, accessibility to newcomers, and a streamlined ruleset compared to prior editions.  It has never been easier to get into Dungeons & Dragons than it is today, and 5e has brought in a massive wave of starry-eyed newbies and long sleeping veterans.  So of course, we have to start here.

If there’s anything from 5e you should be jumping to splice outta the system, its going to be the Legendary Actions, as well as the Advantage/Disadvantage systems.

Legendary Actions

Before 5e, while it wasn’t impossible, it was rather difficult to implement an intimidating boss without using a score of GM tricks.  Alone, a single boss is limited by Action Economy and any group of four or more adventurers could absolutely destroy the enemy before it had a chance to react.  The common GM tricks to handle/mitigate this included HP inflation, adding swaths of minions to the encounter, or just giving the enemy additional actions.  5e took the last point and realized it properly through Legendary Actions.

To catch anyone up, creatures with Legendary Actions are capable of taking these actions either at the end or beginning (in the case of Rezmir, Hoard of the Dragon Queen) of a turn.  They have 3 actions, and often choose from a list of two to four actions.  Some of the listed actions could cost multiple actions, and you regain all actions on your turn.

Legendary Actions add narrative value to the fight, emphasizing the greatness of a boss, and allow them to interact with the party more often.  This is all done without having to artificially extend the fight through massive HP or minions just to let your villain have their moment.

This style of initiative interruption isn’t something entirely new either.  In more narrative games like Powered by the Apocalypse and Dungeon World (moreso emphasized in the latter), the GM acts in-between player actions, turning the battle more into a scene than straightforward combat.  The enemies in these games are constantly interacting with the players and raising the stakes with each hit point taken.  Implementing this in 5e, let alone the plethora of other systems we can use it with only serves to make the fight more engaging.

That being said, despite 5e being the codifiers, I don’t necessarily believe 5e has the best implementation of Legendary Actions in their creatures.

What’s Bad? What’s Rad?

Legendary Actions in 5e tend to boil down to either attacking, skill checks, or perhaps one unique action (often movement).  The epic Adult Red Dragons of lore, at best, can throw down a tail attack, can make perception checks, or do a wingover and fly around.  Vampires, the masters of life and death, can move, make unarmed attacks, and bite.  I think Legendary Actions could be better than that – or at the least flavored better.  Dragons should be able to release plumes of exhaling flame, dealing fire damage and pushing the players backward like 10ft.  Vampires should flavor their simple movement as swarms of bats, teleporting behind the wizard across the field that’s next in initiative, completely shifting the tactical situation at a moment’s notice.

5e does have a few rad cases of Legendary Actions in the game – primarily in Liches and Unicorns.  Liches have the ability to throw down any cantrip they have, as well as a plethora of other options such as Frightening Gaze or their Paralyzing Touch.  Meanwhile, a Unicorn can grant itself or allies +2 to AC, or heal itself when it’s in danger (personally I’d allow them to heal allies as well).  Actions like these keep the identity and spirit of the creature intact and allow you, the GM, to show personality and nuance through them.  Legendary Actions as a whole need to be kept interesting, engaging, and visceral.  Make the narrative itself legendary.

Legendary Actions as a whole need to be kept interesting, engaging, and visceral.  Make the narrative itself legendary.

Legendary Actions have a lot of potential that I don’t believe have been fully realized in the current confines of the system.  Personally, I use a much lesser “Villainous Actions” mechanic for direct antagonists that aren’t quite boss level.  These ones I only give 2 actions to, with one of them being “Kick: +5, 1d4+2.  On hit, push an enemy 5ft away.”  In any case where you feel a halfway important NPC is about to get swarmed by your PCs, consider giving them a fighting chance.  This becomes more necessary for the higher number of players you have.

When & Where

Legendary Actions can be implemented in any system that uses a structured initiative.  Nearly every d20 system can use it, as well as systems like Savage Worlds’ card initiative.  This is also doable with alternative structures like popcorn, group, or queue initiatives.  You’re also capable of just adding initiative structures to games that don’t normally have it, like in FATE.  In FATE I tend to just use Savage Worlds’ card initiative and use Stunts in place of Legendary/Villainous Actions.

Done well, Legendary Actions can make your encounters more interesting, more dramatic, and more dynamic.



Iachini, Michael. “Advantage Disadvantage Probabilities.” The Online Dungeon Master, WordPress, 12 May 2012.

If you’ve been playing 5e to any degree you already know about Advantage and Disadvantage.  To sum it up, roll two d20s and take the higher (advantage) or lower (disadvantage) result.  But how helpful is this?  As the chart to the right will tell you, it’s quite a lot.

Attempting to roll an 11 has a 25% increase or decrease in probability, or the equivalent of a +/- 5 modifier, entirely based on your advantage state.  However, in play we don’t simply say ‘you have a +5 bonus to this’, and this subtle choice encourages the players to focus more on the situation that generated this advantageous outcome, rather than the statistics behind it.  It’s rewarding in a meaningful, non-statistics-focused way.

When utilizing Advantage properly, you want to encourage the players to place themselves in positions where they could potentially gain an edge, and not punish them for giving something a try.  I personally use an “Attempt” rule where players can attempt to do creative things like swing onto a chandelier for a height advantage, but it only uses up their action if they succeed.  If they fail, they’re able to still move and act normally.

If they wanted to jump on that chandelier and roll a 10 and fail, I suggest not punishing them with damage or Disadvantage, but they could now be hanging just at the edge of it.  This is where you could give them a choice to still gain advantage by offering a Devil’s Bargain: if you let go, you still gain Advantage on the attack, but you’ll take falling damage.  Disadvantage should only come up during say, Nat 1’s (if you play with critical failure), attacking in bad conditions (heavy rain and wind), or if the enemies impose it on them.

By punishing players for attempting to be creative, you’re just conditioning them not to do interesting things.  It’s just negative reinforcement at that point.  But when you make the normal answer boring, the players will make accomplishing the interesting their mission.

What’s Rad?

While frequent use of Advantage allows players to feel heroic, epic, and successful, I find that proper use of Disadvantage can lead to just-as-dramatic results.  I have a small bag of 24 paired d20’s hidden in my GM bag that I use for my “Volley Pool.”  One of my favorite moves is just opening up the bag and letting all of them roll out as a volley of arrows and scorching rays fall upon the players.  However, since they’re all being flung out at a volley, it’s all at a Disadvantage.  I’ve never loved an expression more than a player wracked with dread, watching closely as I peel away the high rolls, as a glimmer of hope and relief fills their eyes.  This can create tension where there was none and can allow players to really grasp that they might be in a pinch while still providing a safety cushion against it.  Even against an army, the average 7th level wizard with fireball won’t blink – believing they can wipe out the lot – until they find themselves only narrowly evading a wave of two dozen arrows.  Proper use of Disadvantage can be a very humbling factor for otherwise arrogant players.

When & Where

I’ve never loved an expression more than a player wracked with dread, watching closely as I peel away the high rolls, as a glimmer of hope and relief fills their eyes.

Advantage/Disadvantage can be used anywhere that uses non-narrative dice.  The most common application would be other d20 systems like ICRPG or OSRs like Lamentations of the Flame Princess; however, it can also be used with systems like FATE or dice-pool games like World of Darkness (if you REALLY want to reroll all those dice).  It cannot, however, be used for games based around semi-success; this means Powered by the Apocalypse systems, as well as Narrative Dice games ala Star Wars RPGs/Genesys.  A core element of gameplay in those systems is based on semi-success, or success at a cost – adding Advantage/Disadvantage would only dull the impact and goals of the system.  As an aside, I also don’t recommend using it with Savage Worlds, as the Wild Die itself acts as a unique implementation of Advantage.

I find Advantage/Disadvantage particularly engaging; I would even go on to say it’s one of the best elements of D&D 5e and one of the main draws of the tabletop RPG.  It pulls the game towards healthy narrative structures and acts as a fantastic tool for both GM and players alike.  Whereas Advantage can create triumph, Disadvantage can create dread – as well as hope.

Di’s Addendum

What about Proficiency?

The ultimate goal of System Splicing is to take a look at the best parts of add-on mechanics and find ways to implement them into other systems.  Proficiency is too imperative to the system identity, as it is written too deeply into the core elements and classes of the game.  If you were to implement Proficiency into a random d20 system you would have to majorly rewrite the system to make it fit.  At that point, you might as well play 5e.

What about Short Rests?

While Short Rests are amazing, it is technically an import from 4e – a system that definitely deserves more credit than most players give it.  The only real change and shift from 4e to 5e were that Short Rests were moved from 5 minutes to 1 hour, making it more difficult to rest in general.  However, it still belongs to 4e so I’ll talk more about it when I get there.

What about Lair Actions?

Lair Actions, while fairly clean and interesting, are ultimately just an additional Legendary Action attached to a list of environmental effects.  Just remember that when you use Lair Actions, the effects are ultimately ‘fantastical’ in nature.  The lair is reacting to the power of the Legendary creature, or perhaps has a series of reasonably magical effects, or a natural environment made active and magical.

With the Adult Red Dragon example (D&D Basic Rules, p.8) you have the dragon’s lair erupting in fire, rumbling with earthquakes, and spewing with poisonous vapor.  This is an environment where all those conditions can happen naturally but are violently stoked by the presence of the dragon.  However, you can have lairs that raise and lower with water, or lairs that have statues that fire off various energy blasts.  Ultimately, however, it’s just a 1/round free Legendary Action.

Wrap Up

I think that’s all I can really say about 5e.  Keep your actions legendary and find several dozen d20’s to keep your players on their toes.  Mind the point of what a mechanic is trying to do, and make sure it fits the game well before implementing them.

~Di, signing out.