I have been playing Octopath Traveler now and then recently on the Nintendo Switch. Octopath is a throwback to—or perhaps celebration of—JRPG style games with several particularities, one of which is a turn-based combat system built around attack type vulnerabilities and combatant initiative. Playing Octopath has prompted me to think about how to apply similar systems to tabletop roleplaying games without requiring overly complex mechanics. Below I first explain the Octopath combat system, in slightly simplified form, and then discuss how to apply a similar system to OSR (or what have you) style games.
Octopath Traveler Combat System
Along with basic combat stats such as hit points, each opponent has two attributes that drive the combat dynamics: a shield score and a list of attack type vulnerabilities. For example, Sand Lizardman 2 has a shield score of 2 and is vulnerable to swords, knives, ice, and dark. Hitting an opponent with an attack type belonging to the list of vulnerabilities temporarily decreases the shield score by one for each hit. If the shield score falls to zero, the opponent breaks, which drops the opponent from the upcoming initiative spot and decreases the opponent’s defense while broken. A broken opponent regains all shield points and acts at the next point in the initiative sequences, meaning the best possible outcome, from the perspective of the player, is to force all opponents to skip every other turn. In other words, breaking an opponent effectively stuns the opponent through the end of the next round. Generally, the most effective offense involves breaking as many opponents as possible, because doing so decreases the number of overall opponent attacks and increases the player’s overall damage output. As such, doing a smaller amount of damage using a damage type corresponding to a vulnerability can be just as important as doing a larger amount of damage, especially if the hit is timed well.
The combat system is asymmetric between player characters and opponents. That is, player characters have no damage type weaknesses and never break, though opponents can, using special abilities, inflict a variety of status conditions—poison, silence, blindness, sleeping, and so forth—on player characters. Some conditions can limit player character action possibilities or temporarily prevent a player character from acting entirely, in ways that will likely be familiar to players of other JRPGs. For example, silence prevents casting spells, blindness decreases weapon attack accuracy, and so forth.
This setup is simple, but leads to surprisingly engaging gameplay and tactics. First, the system dashboard presents the upcoming initiative order, so the player can always see which opponents represent the most immediate threats and concentrate fire correspondingly. Second, the number of vulnerabilities per opponent is always apparent, but the particular vulnerabilities are only revealed (by opponent type) after being exploited, or revealed by using a skill (such as the scholar skill analyze). Third, maintaining party capacity to deploy a wide variety of damage types, and timing attacks well, greatly increases combat effectiveness. Missing the capability to deal one or more damage types risks confrontation with enemies that that will be unbreakable. The full list of damage types is swords, polearms, daggers, axes, bows, staves (the weapons) and fire, ice, lightning, dark, light, wind (magic, accessible via skills mostly).
Each of the eight characters starts with one of eight classes: cleric, scholar, merchant, warrior, dancer, apothecary, thief, or hunter based on particular character story background. For example, Cyrus is the only character that begins with the scholar class. Each class provides access to a particular type of damage through weapon proficiencies and skills that the player can unlock by earning and spending job points (a secondary form of experience points). For example, the hunter class can use swords and axes while the thief class can use swords and knives; further, the thief has access to basic fire magic early on through skills. The player can gain access to secondary classes through jobs discovered at various shrines hidden throughout the game world. At any given time, the active party can have at most four members, so the player can configure access to damage types by choosing the active party character roster and by assigning secondary classes to characters after discovering various jobs.
As a concrete example, at this particular moment my active party is Therion (thief), Cyrus (scholar), Ophelia (cleric), and H’aanit (hunter) with secondary classes assigned to Cyrus (as thief) and Ophelia (as hunter). This allows my party to deal the following kinds of damage, by member:
- Therion: knives, swords, fire (skill)
- Cyrus: staves, knives (thief job), Swords (thief job), fire (skill), ice (skill), lightning (skill)
- Ophelia: staves, axes (hunter job), bows (hunter job), light (skill)
- H’aanit: axes, bows, lightning (skill)
Here I have plentiful access to damage from swords, knives, staves, axes, bows, and most magic. This party lacks the capability to easily deal dark, wind, or polearm type damage. (I have ignored the boost system intentionally for the purposes of this post, though using boosts is quite important to tactics in Octopath due to how applying boosts allows the player to increase the number of hits for a particular damage type.) The following short video shows how this works for the video game in practice:
Below I suggest a number of slight system modifications for implementing a similar system for OSRoWHY games. After deciding upon the basic structure of rules to apply, most content details could probably be handled easily enough by rulings.
I would first assign each character and monster type a speed score to determine place in the initiative order. For player characters, this could either be by class, by dexterity, or by some combination of class and dexterity. For a game where ability scores are less influential overall—such as OD&D—I would probably start with class (magic-user ⇒ 1, cleric ⇒ 2, fighter ⇒ 3, thief ⇒ 4) and provide +1 for exceptional dexterity and maybe +1 for weapons that seem agile. For a game where ability scores are more influential overall—such as B/X, AD&D, or 5E—I would start with dexterity (12 or less ⇒ 1, 13-15 ⇒ 2, 16-17 ⇒ 3, 18 ⇒ 4) and provide a +1 for class competency (perhaps +1 for fighter-types and +2 for rogue-types). In this and all following examples, combatants with higher speed scores act earlier. Keeping the scale of speed scores around 6 will decrease the difficulty of manual handling. The referee could determine opponent speed by ruling, assuming an average of 3 or 4 and adding or subtracting a point or two based on whether the opponent seems like it should be quick (pixie ⇒ 6) or slow (ogre ⇒ 2). For a more predetermined approach, or for people who appreciate some degree of textual deference, the movement stat is available (1974 OD&D Monsters & Treasure, p. 4, Move in Inches; 6 ⇒ 1, 9 ⇒ 2, 12 ⇒ 3, 18 ⇒ 4, 24⇒ 5, 25+ ⇒ 6).
I can see several potential ways to accomplish the practical tracking of initiative order, including index cards with speed values or a simple sequential game board of 12 spaces—six spaces for the current round, six spaces for the following round—with tokens for each player character and type of opponent, numbered according to the current and following rounds—something like 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6. Using a game board in this way would more or less replicate the way Octopath presents the initiative order. The referee could also just perform a countdown from 6 for each round—perhaps a countdown would be easier if playing by video conference—but would need some way to keep track of opponents that have been broken. My guess is that index cards would work best overall, but it would require some play testing.
HD seems like a reasonable stat from which to derive something like a shield score. My first pass might be HD / 2 (round up). The division is simple enough to do mentally—HD 5/6 ⇒ shield score 3, for example—and ensures that enemies are likely to break before being defeated, all else equal. In a more involved system, such as AD&D or 5E, the HD or challenge rating might work as the shield score verbatim. Another approach that appeals to me given OD&D assumptions: encounter table dungeon level ⇒ shield score; this would maintain a rough connection between monster strength and shield score but also naturally scale up weaker monsters on lower dungeon levels without otherwise engaging in numerical inflation.
Finally, and perhaps most substantially, the referee would need to determine the types of damage and corresponding opponent vulnerability lists. There would be worse places to start than the 5E SRD damage types; I could also imagine many quirky taxonomies based on close readings of whatever your favorite game text is. Particular vulnerabilities could be intuited by ruling easily enough. Does an opponent seem to have some form of elemental affinity? Cold-related monsters are obviously vulnerable to fire. For some reason, slimes and oozes seem to me like they should be vulnerable to lightning. Skeletal or chitinous monsters seem naturally vulnerable bludgeoning. In OD&D, giant type monsters roughly correspond to the fair folk, so a vulnerability to iron could be mythologically appropriate. What about all of the weapon types? The vulnerability list could be a way to effectively smuggle in a weapon versus armor table, and would make weapon choice most relevant when confronting man-type opponents (to use the OD&D terminology). I imagine polearms or spears being particularly effective agains larger monsters and missile weapons particularly effective against flyers.
A ruling-based approach like this would probably be enough to get the system off the ground, and the referee could build up lists of vulnerabilities through play rather than trying to frontload it by taking a spreadsheet approach. Additionally, think about how you describe details of opponents to players and how your description can gesture toward vulnerabilities; this is a way to expose game surfaces to players through the diegesis or fiction rather than being excessively or indecently mechanical. You could let the players build up a deck of monster index cards representing what the player characters have learned through play, which then would do double duty as initiative tracking prosthetics.
Such a system could easily plug into various other subsystems. For one example, morale: trigger a morale check if 50% or more of opponents are ever broken, defeated, or captured at any given time.