HOW DO YOU DIFFERENTIATE YOUR CHARACTERS?

You could give them all different skills. Maybe have like a base skill that everyone within their own class knows (like all tanks know Rage, all healers have Heal) and then have each character have his own set of skills.

Like:
Mage #1
skill 01 - Chant
skill 02 - Fire
skill 03 - Bigger Fire

Mage #2
skill 01 - Chant
Skill 02 - Water
skill 03 - Flood

Mage #3
skill 01 - chant
skill 02 - Earth
skill 03 - More earth

You get the idea.

There are a bunch fo things I do to differentiate classes and in my games. But I think that instead of listing them all abstractly I'll give you an example of three physical, agility-based classes from the same game (The Unofficial Squaresoft MUD). Although these are based on Final Fantasy staples and you'll recognize a lot of the skill names, they play a lot more complexly than the source material.

I'm gonna try to specifically list the things I had to think about with regards to making these classes different from each-other, like different kinds of skill rotations or slightly more benefit from certain stats.



Archer
Stats: +15% HP, +10% MP, +40% agility
Equipment: bows, crossbows, shields, light armor
Shields can only be used with crossbows, not bows
Bows are strength/agility hybrid damage, crossbows are pure agility damage

Example skills:
Charge Attack - Start charging up, preventing your auto-attacks from firing. Use the skill again to release, dealing damage based on how many auto-attacks you would have gotten.
Arm Aim - Physical damage and a minor chance to paralyze target. There are a few other similar skills that inflict different ailments.
Doubleshot - Physical damage to 2 random targets. There are upgrades that hit 3 and 4 targets.
Hunting - Physical damage, and increase your crit rate if this deals the killing blow.
Aim - Increase your whole party's crit rate.
Animals - Summon animals to continuously do stuff for the next three turns. You can keep using other skills while the animals are appearing; it doesn't use up your turns. You can choose which animals will appear; new animals are unlocked as you level up. They do things like attack, poison, heal, revive, etc.

This whole job is largely about locking down both the enemy and yourself, and finding ways to deal damage through that lockdown and win before the enemy can act again. Its direct damage is pretty unreliable, either because it uses random targeting or because it relies on crits.

A typical archer skill rotation might be to use Arm Shot to lock down an enemy, then use Animals to deal damage over the next three rounds, then use Charge Attack to charge up for three rounds and release the charged attack just as the enemy breaks out of paralysis. Or they might keep Animals running at all times with just healing effects, and use other less risky attack skills.

Archers care more about strength than the other two agile classes, since they will always be using either a hybrid weapon or a shield. (High level shields require high strength to equip.)


Thief
Stats: +10% HP, +10% MP, +45% agility
Equipment: daggers, boomerangs, light armor
Daggers are strength/agility hybrid damage, boomerangs are pure agility damage
However, all thief abilities do pure agility damage regardless of your weapon type
Equipping a dagger will still cause your auto-attacks to do hybrid damage

Example Skills:
Steal - Steal a combat item from an enemy. You can only hold one stolen item at a time. Stolen items are random but enemies are more likely to give you specific certain items.
Toss - Toss your stolen combat item. About a third of these deal mondo elemental physical damage, a third of them deal pretty good physical AOE damage plus a minor ailment like Power Break, two of them buff your party with haste and regen, and one heals your party.
Steal Coins - Steal money from an enemy. More from bigger enemies. Long cooldown.
Coin Toss - Use up the money you last stole to deal damage based on the amount stolen. More money = more damage. Insanely strong skill, limited by Steal Coins's cooldown.
Steal MP - Steal MP from an enemy. You can't steal more MP than you're missing.
Free Energy - Deal damage based on how much MP you last stole. Unlike Coin Toss, the MP isn't used up by this skill. This means that casting lots of magic to quickly use up your MP directly translates into dealing more damage. Insanely strong skill, limited by the fact that Thief has no MP-using skills, and you must rely on your secondary skillset.
Thievery - Deal damage based on how many times you've stolen since the last time you used Thievery.
Mug - All your steal skills now do damage too.

Thief is based entirely around stealing resources from enemies that are then used as ammunition for your attacks. Its bread and butter is the highly random Steal/Toss, but as you get more skills the job becomes more reliable and gains ways to mitigate its randomness. The cooldown skills are much more reliable, and will eventually make up a good 25% of your turns, while Mug helps out as well. This job deals more damage than archer but lacks a way of stunning enemies, so you'll need to use your secondary skillset or rely on party members to stay alive.

This class also has the ability to steal equipment, but only if you get leads on where to find equipment. To get the leads you have to do missions for a troupe of thieves. Between that and Steal Gold, this is the class that gets you rich.


Ninja
Stats: +15% HP, +35% MP, +25% agility
Can equip two weapons, doubling the number of auto-attacks
Equipment: daggers, boomerangs, whips, ninjaswords, hammers, light armor
Hammers are purely strength-based, boomerangs are purely agility-based, and the other three weapon types do strength/agility hybrid damage
Different hybrid weapon types have different damage ratios, favoring strength or agility more
Ninja's magic skills always deal agility-based damage, but the physical skills deal the same type of damage as your main-hand weapon

Ninjas have a unique resource: shadows. You gain 1 shadow every time you evade an enemy attack. Various equipment and counterattacks can affect your evasion rate. Most ninja skills also either generate or cost shadows.

Example skills:
Image - Evade the next 2-3 attacks and generate 2 shadows. Long cooldown.
Shadowbind - Paralyze an enemy. Costs 1 shadow.
Throw Magic Scroll - Throws a fire, ice or lightning scroll, dealing magic damage to all enemies. You can choose which element to use. Scrolls are bought in shops.
Throw Shuriken - Throw a shuriken at one enemy for light physical damage. Shurikens are bought in shops.
Throw Shadow Weapon - Throw shadow copies of both of your equipped weapons at the enemy, dealing heavy physical damage. Costs 2 shadows per weapon.
Kakka - Buff yourself with an effect that regenerates your thrown scrolls and shurikens. Costs all your shadows, and lasts longer the more shadows you have.
Tonko - Buff yourself with a defensive barrier, letting you sometimes evade even magic. Costs all your shadows, and lasts longer the more shadows you have.

Ninjas are the tankiest of the agile fighters, and their whole skillset is based around evasion. The more they evade, the more shadows they get. As they build up shadows they have to choose whether to use them to deal damage, replenish resources, or survive. Ninjas don't ever have the survival of a true tank class though; many bosses can still kill them in one hit if they don't dodge. The evasion stat is definitely more important for them than it is for other classes. Ninjas can also paralyze enemies, but deal minimal damage while the enemy is paralyzed, since there are no attacks to evade.

A ninja's skill rotation varies a lot from one fight to the next because evasion is still very random. You might get shadows three times as fast against one enemy as against another. Shadows also carry over between fights so they play out even more differently - you might start one fight with 0 shadows and the next fight with 8. However this randomness feels very different from Thief because it affects your order of skills rather than determining which skill you get to use.

In addition to dealing with shadows, they also have to spend a little bit of gold on throwable items. They're also the only agile class that uses MP; it's only for a few skills, and they don't use very much, but you'll need to find an inn eventually. So they definitely have the most to keep track of out of these three classes, and are also the most expensive.

The biggest thing is to know how to make cool skills -- I mean that mechanically. Knowing the basics of coding in Ruby (or Javascript for MV) is important. You don't need to know a ton if you use Yanfly's "Lunatic" sections, but you need to start looking at code and trying to change things just to see if you can make them happen. I keep all of my games unlocked so that you can open them up in Ace to examine them for yourself, if you wish.

Knowing even the basics of code, or how to use other people's work (although please learn some code -- you'll thank yourself later), you can turn a boring skill into something greater.

Pyroclasm - 15 MP - Deal extreme Fire damage

might become

Pyroclasm - X MP - Consume all MP to deal Fire damage based on current MP

or

Pyroclasm - 15 MP - Deal extreme Fire damage and refresh the duration of Burning and Defense Down ailments on all foes

While these are still simple skills, they better suit different archetypes. Maybe the first variation is for a lancer who only sometimes uses spells or low-MP buffs, and thus isn't too concerned with MP. Maybe the second one is a sadistic mage who benefits from hexing many enemies at once, letting Pyroclasm extend their combos.

The next thing is to know your characters. Karsuman (co-creator of Visions & Voices) and I talk a lot about his/our characters. When I was doing solo projects, I would bounce them off of other people as well as go through their interactions in my head. For Super Battle Kiddo Experience, I had a checklist of which character pairs had not talked one-on-one yet. And so on. Doing this lets you know your characters as more than "rogue girl who likes money" -- although knowing that is important! But if you also come to realize that she's comfortable in caves because of her outdoorsiness which lets her comfort the freaked-out priestess who she otherwise doesn't along with, wow, you just designed a passive skill.

Shadow Guide - Passive - Whenever Geraldine misses, Lina makes a double attack on that enemy and puts Speed Up on Geraldine.

Throw this onto the rogue after a scene with both characters and bam, you have both character development and enhanced your gameplay in a meaningful way. Geraldine might not be the best with weapons, but on turns you don't need to heal it now doesn't matter if she misses. Especially, if:

Determined Blow - 0 MP - Attack an enemy for moderate Phys damage. If it hits, Geraldine and a random ally get 3 MP.

Hey, looks like Geraldine has an attack command fitting a priestess. And now, after our cave scene, it's going to get even better because her poor Speed stat doesn't matter as much -- even on a miss, Lina will just attack instead. You won't get the MP, but you'll deal more damage.

But I guess we now have a different bugbear: healing. It can be super boring!

Prayer - 12 MP - Lightly heal the party
Cleansing - 6 MP - Moderately heal an ally, and remove Poison/Bleed/Burn

Effective, but boring as heck. Let's further Geraldine's themes of MP manipulation, being a holy figure, and being scared of the dark. We can also play with a love of chocolate, and that we wanted to promote item usage in our game.

Sunrise - 8 MP - Deal moderate Light damage to all foes. Dark-aligned foes grant 2 MP to the party when hit
No Time for Fear - Passive - When Geraldine hits a Dark-aligned foe, her next heal is 33% more effective

Now she has a utility spell and benefits from being put in the party against certain foes. She might be freaked out by demons and caves, but she has learned to use that to her advantage.

Dip in Chocolate - Passive - When Geraldine uses a beneficial item, the target ally is cured of a random ailment

If you have some buff items in your game (since Geraldine probably doesn't need to use health potions), Geraldine can get some curative kick in there. Mmm, dark chocolate. If we don't give her any status cures besides Cleansing, this won't overlap too much.

Prayer - 12 MP - Lightly heal the party. Heal amount is partially based on the ally's Defense
Firefly - 2 MP - Target ally will attract enemy attacks more often. Whenever that ally is hit over Firefly's duration, they gain 1 MP.

Now Geraldine can take care of our tank a bit better, or maybe even a mage character who can resist the spells of an enemy mage and gain MP from taking the hits.

Hopefully this gives you some insight as to how I work. When I'm not at actual dayjob work, I'll pull out some of Karsu and I's skillsets for our current game and explain how and why we designed them.

I'm on the downer side here. If your battle mechanics can't accommodate 12 different story characters easily then maybe they shouldn't join in a battle capacity. Just because someone joins your team doesn't mean they have to fight.

Just variations on the main groups of spellcasters, warriors, and rogues, then further categorizing them by healing, damage dealing, buffing, debuffing, support skills, then further by skill targets (single/group/AoE), and then equipment types. The usual.

Have each one use a strict different payment type for casting skills. One strictly uses MP for skills, one uses TP, and maybe one uses HP. To use HP to cast skills, I'd recommend this script.

You'd be surprised how much skill payment changes how you use a character.

Yes, using your health to cast a skill rather than MP does in fact further things. You're not going to use a character that uses their health to cast skills in the same way you use one that uses MP. Same with TP. Each skill cost has vastly different effects when being used on their own. Of course you'd have to differentiate skills accordingly between characters depending on what they use to cast skills. That's a given.

You don't need to think harder than this, you just need to know what you're doing.

The OP asked how they could make their characters have their own identity in battle, not story.

then again, I played a bit of Dragon Quest III again recently, and the very simple straightforward class and skill designs were quite satisfying.

Something to be said for simplicity, 'tis all.

author=LockeZ
It's all very closely linked. Their battle styles should obviously all be derived from their story differences; you want that shit to feel meaningful, not random.

But there's also a lot more to it, as Craze was saying. It's not enough to just have your Dark Knight character use HP instead of MP to cast skills, and otherwise be identical to the Fighter. That difference needs to have other differences it interacts with, creating a unique play style. You can give them unique armor that increases or decreases max HP instead of defense, HP regen buffs, self-dots, drain attacks, skills that affect how effective healing on them is, skills that passively heal them under various circumstances, taunts that cause them to already take more damage, lower defense that turns them into even more of a glass cannon. They can have buffs or self-penalties that temporarily change their max HP, or skills that temporarily change the HP cost of other skills into a bigger or smaller cost or into an MP cost, so that the values of the costs are more manipulable. Counter abilities that interact with all of that other stuff by making them heal themselves, or take MP damage instead of HP damage, or distribute damage across allies, or just counterattack.

And then you can do lots of other things as well that don't necssarily play off of the HP skill costs but still add more differences that make the player think more, like different ways of learning new abilities, different stats and equipment, different elements, different amounts of wind-up time before they get access to their best attacks, different buffs, different levels of self-healing, access to different ailments, more stuns and interrupts, better mobility, and other various generic shit like all that. All of these kinda of things will weave together to help give them a real identity as a character that plays very uniquely instead of just having a single elemental difference. And as you create combinations of these things, it's important to think about how they all interact with each-other, and to test the character extensively to make sure that the combat situations they create are interesting and fun.

Yeah, of course. As I said before, you'd need to set up skills specified for each character depending on what skill costs they use and such. Again, that's a given. I feel like the OP is already aware about the little changes they can make. I'm trying to give them ideas to build off of, not micromanage their game.