Immutable Time Travel


I read Homestuck for the first time around the same time I rewatched Terminator (1 and 2), and it got me thinking about using travel through immutable time as a game concept. The upshot of immutable time is that it lets you send the players throughout time without having to figure out how the minor and major changes they make would alter the future (which, in any kind of non-predestined time, would be a lot). The drawback is that you instead have to figure out how to keep them from changing anything. The following is an overview of how this kind of time travel would work (largely patterned on how it works in Homestuck, so minor spoilers for that if you plan to read it), and includes several elements to try to keep the scope of attempting to change the past manageable within a game framework. (This is presented as in-character advice from a time traveler.)

1) Time is internally consistent

Time travel doesn’t actually let you change anything. Circumstances will conspire to negate whatever change you’re attempting to make. Killed your grandfather before your mother was conceived? Turns out your grandmother never mentioned her husband’s twin and his untimely murder. Attempt to travel back and tell yourself something on a day you know you didn’t meet yourself in your own timeline? You’ll never actually get to the meeting due to seemingly random accidents, or something will happen to erase your memory of the meeting in the past, or some other bullshit.

Your best bet, when time traveling, is to know as little as possible about any events you’re trying to interact with. Your ignorance doesn’t mean that things aren’t objectively true (you still can’t actually change anything, from the point of view of someone who does know what happened). But at least you won’t know for sure whether what you’re trying to do is futile.

2) Information ignores paradox

Sometimes information-based time loops become stable with no true cause. Brought yourself back the same formula for cold fusion that you gave yourself when you were young, and told yourself to pass on once you discovered time travel? No problem. Pulled a time-travel Oedipus and became your own father, creating a Y chromosome from nowhere? Gross, but not a paradox.

Maybe the information comes from the zeitgeist. Maybe it comes from the gods of time fucking with us. Nobody knows for sure. Maybe someone will pass the secret of how it’s possible through a self-generating time loop at some point.

3) Matter, however, can’t get stuck in a time loop

Matter is much easier to degrade than information. Reality seems to be fine with the secrets to a better watch coming from nowhere, but the watch itself needs a provenance. If a time traveler gives you an object, you cannot give that same time traveler the same object to take back to you. You can take it apart and make an identical duplicate, as long as the matter for the duplicate came from somewhere real (or you can just find where the item originally came from, send that one back, and keep your version). It’s all down to a loop being infinite: a piece of finite matter stuck into it would gradually erode.

Don’t even try to mess with this, it can get really wonky, really quickly. Note that a really obnoxious exception is that immortal, ageless living things can actually come from nowhere, since they regenerate their bodies with new matter from the environment; they can just expect memory loss somewhere along the line before they start the loop over again.

4) You can fork a timeline, but you absolutely shouldn’t

In extreme circumstances, it is sometimes possible to change something. Despite the implications in rule one, there isn’t actually some kind of omniscient deity keeping you from changing things. Sometimes events seem weirdly contrived to try to keep you from making alterations, but if you had a god’s view of the situation it would all make sense as a series of interlocking causes. Reality’s defenses against changing the past are passive, and if you really, really set your mind to changing something in a way you know for a fact is a change, you often can.

Don’t do that. You are no longer a resident of the prime timeline if you do. Back in reality, you made a different decision, and things proceeded as they always had. You and the entire reality you forked off are now doomed; the universe doesn’t have enough energy to keep forks going for very long. If you stay there, you’ll start to notice that entropy is on overdrive, and everything quickly begins to fall apart, including your own cells. You can time travel back, usually as the special paradoxical exception that got you to reconsider making a change in the prime timeline. Then you’ll likely die. Gruesomely.

5) Because reality is sturdy, it’s worth it to try things

You will not step on a bug in prehistory and totally change the course of evolution (unless you already did). Your modern flu will not start a new plague that wipes out Europe (thought it might have started a documented one). You will not accidentally give Genghis Khan the future tech he needs to start the industrial revolution centuries early and conquer the globe (though he might have you burned as a witch). Really, unless you’re trying to fork a timeline by enacting something you know is a change, the worst things that can happen are that attempting to change things gets you hurt or killed with no alterations, or you find out that you were responsible for something that already happened anyway.

Want to save a loved one that died in an accident? Just be ready to leave a convincing replacement corpse and it might all work out. Need to find out a piece of long lost information? Wander around asking questions in your future clothes and it’ll be fine, in the grand scheme of things. Timeline predestination is freeing, in a way: if it’s possible to succeed, then you always did, if it’s impossible, then you’ll find out pretty quickly, and if you fuck up grandly along the way, the future was always a product of that catastrophe.

Just keep the rules in mind, try not to learn anything that makes you certain you’re going to fail because you already did, and experiment. A time traveler with guts and cunning can accomplish a lot of marvelous things… that were always destined to have happened.

Legacy Superheroes

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Season 2 of Young Justice finally showed up on Netflix, and got me thinking about one of the things that DC has always done extremely well: worldbuilding through character inheritance.

The DC universe has such a robust mythology of archetypal characters, it’s easy to introduce a new character that can rely on other characters for the heavy lifting of powers and such, and provide a foil to differentiate the character. For example, you don’t have to come up with a whole new explanation for how a new speedster works; that character is tapped into the Speed Force, which provides some interesting constraints and possibilities for development. Young Justice is basically all about this: nearly all of the characters are legacy heroes based on a Justice League member. The DC Universe MMO does something similar, providing character building blocks from established characters to mix and match.

There are a couple of interesting ways to profit from this in your own supers games: top down and bottom up.

Top Down

The first method is to use an existing setting or make your own with a lot of nailed down origin concepts. The players then pick from these origin types to control what powers they can access, and what baked in story tropes they’ll be part of. Obviously, stated that broadly, it’s something that lots of supers games do: are you a magic hero, a mutant, a scientific accident, and alien, a highly trained human, etc.?

What I’m advocating drills down from those broad classifications to actually latch onto the key setting elements of the universe. Using Young Justice as an example, players might pick:

  • Alien (Kryptonian): You can take some or all of the Kryptonian powers (invulnerability, super strength, flight, x-ray vision, freeze breath, etc.). You are vulnerable to kryptonite, and draw your powers from the yellow sun of Earth. You are likely related in some way to the House of El, and inherit its enemies.
  • Alien (Martian): You can take some or all of the Martian powers (telepathy, telekinesis, shapeshifting, phasing, etc.). You are vulnerable to fire. You are among the last of your kind, and hunted by ancient enemies from your home.
  • Atlantean: You can take powers related to living undersea (water breathing, swimming, strength and durability, marine animal control, hydrokinesis, etc.). You are part of the Atlantean feudal system, and beholden to its politics.
  • Clone (Copy): You are an exact copy of an existing character, and may take that character’s powers (possibly reduced or enhanced based on that character’s backstory and limitations). You may or may not have that character’s full memories, and may have been created as a sinister replacement. You will struggle to find your own place in the world.
  • Clone (Hybrid): You are a combination of two or more characters (and can mix and match other origin types), and can take powers related to either or both. You were likely created as an experiment in improving on the original stock, and may have in-built conditioning that you must overcome. You will struggle to find your own place in the world.
  • Human (Trained): You have advanced martial training from Batman, Green Arrow, the League of Assassins, or some other skilled teacher, and should particularly focus on the martial arts favored by that group. You likely have a conflicted relationship with your mentor, and often inherit his problems and enemies, but can also rely on your adoptive family for help in a pinch.
  • Human (Magic): You were trained in magic, likely in an idiosyncratic style common to a parent or other mentor such as Zatara. You are part of the small and eclectic community of mystics, and may operate under requirements and allegiances that are extremely arcane to your team.
  • Human (Tech-Enhanced): Your powers come from cybernetics, power armor, or other high-tech devices, and you should choose which company invented them. You will be beholden to that originator for replacements and improvements to your tech, which may create trouble for you.
  • Meta (Speedster): You gained your powers from a meta event or inheritance/transfusion from another speedster. Unlike typical metas, your powers are specifically informed by the Speed Force (though you may also feel an obligation to deal with any other metas created by the same event that gave you your powers), which earns you specific enemies and allies in other speedsters.

Essentially, you can’t take powers without in some way tying the character in to the larger narrative of the setting, immediately attaching allies, enemies, and potential problems before the start of play.

Bottom Up

The opposite method is good for getting a lot of player buy-in (and getting them to help the GM worldbuild): instead of picking from a pre-defined list, each player explains how his or her powers are actually in line with a setting archetype.

For example, a player rolls up a speedster, and then works with the GM to invent the idea that speedsters are somehow apart from other characters empowered by some meta event, and actually have more in common with other speedsters. The GM and player negotiate out the idea of a Speed Force, a sense of responsibility for other meta villains created at the same time, and invent various Flash characters from history that are well-known holders of the same powers.

The key difference in any other game where you pick powers and then try to justify them is the sense of the legacy. In the example, you’re not making The Flash, a character that, as far as he knows, is the first speedster in the setting and will gradually uncover thematic ties as the GM has ideas. Instead, you’re making a character with precedents that you’re going to negotiate with the GM up front: you get a say in elements of the setting that your character will be the focus of, and you help the GM by providing a whole bunch of setting ideas that you’ll be interested in. The GM doesn’t have to throw a bunch of ideas at you to see which ones you bite on, because you’ve already indicated that you’re into the meta events, Speed Force, strange relationship to other speedsters, etc.

Obviously, this method works better for players comfortable with taking that kind of ownership of inventing setting details so they can then happily interact with them in play.

A Few E6 Hacks


After all this talk about variations on Epic 6th over the past few weeks, I thought I’d devote a post to a few modular ideas for improvement I had in the process of writing them.

Bonus Feat Classes

One of the classic problems with E6 is the difficulty it causes the fighter (and, to a lesser extent, other classes that get bonus feats). Once characters have hit their level cap and started piling up additional feats, the character whose class advantage is extra feats starts to look much less attractive next to characters that have a bunch of special abilities and a bunch of feats.

A potential fix for this is that, at level cap, these classes upgrade their bonus feats to also qualifying for better feats. For each bonus feat you got as a class benefit (either a broad choice, small list, or specific feat), you also add +1 to numerical values to qualify for feat prerequisites once you start earning post-cap feats. So, for example, in straight up E6, a Pathfinder character who is a 6th level fighter gains +4 to prerequisites for his four bonus feats. He qualifies for feats that require character level or base attack 10, and treats all his ability scores as four higher for feats with ability prereqs (even a fighter with below-average intelligence can eventually figure out Combat Expertise, and one could be fairly clumsy and still try two-weapon fighting).

This bonus should probably affect Caster Level as well, to allow Wizards to potentially get higher level item creation feats. For multiclass characters, I’d suggest limiting it to doubling the effective caster level (e.g., a wizard 1, fighter 5 counts as CL 2 for feats rather than CL 5).

If the feat has any scaling bonuses, those go off of the actual score, not the modified one. This ability affects availability of the feat, but not its scaling.

For classes like ranger and monk who get access to feats that allow them to totally skip prerequisites, you may wish to not count those particular feats. But it’s probably additional bookkeeping that isn’t much of an actual limit.

Ability Score Retraining

Particularly in a modern game with a lot of downtime, there may be some degree of verisimilitude to be gained by allowing player characters to change their ability choices. Without the regular ability bumps at every four levels, E6-based games don’t really have any way to model hitting the gym.

This system has players keep permanent track of their point buy pool. Over time, you can lower one or more ability scores to return points to the pool and spend them to raise another ability. This can take as much time as the GM thinks is reasonable for a workout regimen. I’d suggest a default of 1 month per point respent (which means one could go from an average score to an 18 in about a year and a half, which seems decently realistic).

As a side effect, this can also model ability drain in a world without access to Restoration: having an ability “permanently” damaged returns its points to the pool, and you have to go through months of physical/mental therapy to restore the damage, but the points aren’t really lost.

If you’re running a version that includes one or more ability +1s from levels that are multiples of four, I’d suggest actually treating those levels as giving the character +4 additional point buy points to avoid having to deal with a weird floating +1. (I’d actually suggest doing this anyway, as it’s a good fix for the laser focus on improving prime requisites to ludicrous levels that’s so common in 3.x).

If a player deliberately lowers an ability score that was serving as a feat prerequisite below the minimum qualification, the player should replace the feats in question (and any feats dependent on them) at the same time. If Intelligence bonus goes down, the player needs to remove the granted skill ranks.

Class Retraining

As mentioned last week, E6 variants can put the spotlight on the differences between NPC and PC classes and what those mean for how much formal schooling you’ve had. Within a 3.x framework, Commoner represents having no formal schooling, the other NPC classes represent merchant apprenticeships, army memberships, and other methods of learning-while-doing, and PC classes represent being taught elite skills from the best of the best.

This leaves open the door that characters should be able to multiclass to a better class once better schooling is available. The farmer that gets called into a militia, finds she has a knack for it and stays with the army for years, then impresses an elite swordsmaster might be a Commoner 1, Warrior 4, Fighter 1. And in normal, uncapped progression, that might be fine. But in a capped progression, that character is now stuck, never able to transcend her peasant roots.

So in a capped game, the GM might allow characters to trade up levels in Commoner for a better NPC class, and in an NPC class for a PC class. This can take time and/or XP as makes sense to the GM, and should generally follow a couple of rules:

  • This isn’t a gestalt: you lose the old level, gain the new one, and retain any choices you’d made previously (e.g., skill points remain spent).
  • The upgraded class should generally be one that doesn’t require losing any abilities. Commoner, by virtue of being terrible at everything, can easily transform into any NPC class. Expert has enough skills that it can only upgrade to rogue, ranger, or other classes with at least six skill ranks per level. Warrior can only go into full BaB classes with at least a d10 hit die. Adept can only go into other caster classes. Aristocrat may require very special handling.
  • Adept spellcasting could prove strange. Ideally, if you know an adept is looking to eventually upgrade, her spell list should be pared of any divine or arcane spells that won’t be available later. Spells per day and known should remain those available to the highest level of adept taken until the PC class exceeds that (e.g., an adept 6 training into a wizard keeps casting as an adept 6 until shifted into an adept 2/wizard 4; at that point, the wizard 4 grants better casting than the adept 6, and the player can ignore the adept levels for spells per day purposes from then on).

As a side note, this system may actually work for 5th edition as well: “NPC” classes become just taking a background plus a generic small hit die and the standard proficiency bonus (e.g., you could be an Entertainer 5, which just means the Entertainer background for proficiencies, proficiency bonus +3, 5d6 hit dice, and no class features). That character can then upgrade to an adventuring class (gaining class features and replacing the d6 hit die with a bigger one, if the class grants it). You might even create a midpoint where the character has an adventuring class but not that class’ selectable template (e.g., you could go from Entertainer 5, to Bard (with no college) 5, to Court Bard 5).

Epic 10th (E6 Shifted 4)


Let me tell you about the random idea I had in a dream a few weeks ago! Unlike most ideas that come to me in dreams and seem totally amazing at the time, this one actually held up after I fully woke.

Epic 6th is the idea of capping D&D/Pathfinder at 6th level (and getting feats for subsequent level-ups). I suggested a variation down to E1 last week, and I’ve mentioned some arguments for E8 before. This is another simple modification to the concept:

All PC-race adults are presumed to start at 5th level, and characters cap at 10th level before they start to just gain feats as normal for E6.

This should result in some interesting benefits over normal E6 (and normal 3.x in general):

  • Starting adult PCs are pretty burly, more on the order of 4e PCs with a pile of HP that means they can handle a lot of punishment. Starting adult PCs should feel like they can have a bit of backstory to them, rather than just being callow youths. You can assume the PCs already farmed goblins and wolves in their backstories, and throw them right into more interesting modules (or make them take on a really ridiculous amount of goblins).
  • If it’s important to you, you’ve plugged the problem where 1st level Wizards start much older than “easier” classes, but then anyone can multiclass and pick up their first level of Wizard almost instantly (because now that level is only 1/5 the levels the Wizard started with).
  • Discrepancies in midlevel special abilities are ironed out (e.g., in Pathfinder, some cleric domains get a special ability at 6th but some don’t get one until 8th, so normal E6 makes the 8th level bonus domains less attractive, but this way they all get such abilities).
  • Low-level NPCs are even more of a long-term threat to PCs than in regular E6: 10th level PCs have to respect being hassled by 5th level guards more than 6th level PCs have to respect 1st level guards. You get more mileage out of standard NPC stat blocks and just adjusting how many the PCs face.
  • Unlike normal D&D, you have a lot of room to run a Harry Potter/the Magicians/Name of the Wind-type school campaign. Start students at 1st level and have them level to 5th by graduation.

In a setup of this type, using NPC classes to differentiate NPCs is likely to be very important. It makes a big difference if a town guard is a Commoner, Warrior, or Fighter when they all have a minimum of 5th level. There’s a lot of room to use access to better classes as a way to differentiate characters by education. Who wins in a fight between the 10th level Commoner who’s the town brawler, the 7th level Warrior who’s actually been a soldier in the wars, and an unblooded 5th level Fighter straight out of dueling school?

The big drawback of going up to 10th level is that it opens up something that E6 deliberately excludes: the common availability of 4th and 5th level spells. In particular, daily access to Scrying, Stone Shape, Teleport, Wall of Stone, Sending, Fabricate, and Raise Dead can blow out the low-fantasy feel of E6 (and even the spells that are just continuations of earlier ones can begin to cause the linear fighter/quadratic wizard problem). GMs that try this are advised to make careful revisions to the spell lists to make sure they’re happy with what the players will get to at the high end, possibly drastically modifying problematic spells or removing them altogether. As an upside, a few of the spells (e.g., Atonement, Death Ward, Break Enchantment, etc.) are somewhat key to the math of mid-level D&D, so E10 makes them available without having to resort to house rules for rituals.

The only other drawback I can think of is some players really dislike not starting at 1st level, because they don’t feel like they’ve “earned” the levels honestly. Make sure you don’t have any players with such feelings before instituting the hack, or there might be some pushback.

Ultimately, this hack should have a number of interesting benefits gained from recontextualizing the ordinary play mode of E6, with only a slight push from the gritty, low fantasy it usually represents up into the top of heroic fantasy and the threshold of wuxia.

And since I’ve been talking about variations on E6 for the past two posts, my plan for next week is a few options for whichever variant of E6 you use.