A timer, once you die you can't re-use that race, and if it drops to a certain number it's locked for all players.
Alternatively, new races can be created, or once there's a dominant race, the server rolls back or w/e.
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An MMO, or, hell, just an RPG, that's turn based but offers deep systems, like Skyrim. Imagine everything's rendered in 3D, and unit moving is as simple as Fire Emblem, and any attacks are played out in dynamic 3D scenes rendered in-game. Where a character is hit is tracked- someone who takes an arrow to the leg won't move as fast, someone who's arm gets sliced deeply won't be able to swing a heavy sword, and someone who takes a stab to the chest will bleed, and fast.
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Weapon crafting is a large part of the game, rarely are you ever handed a weapon directly, rather, you must craft them.
Crafting is rather simple, however, say for a sword:
First, you provide or choose the design for the blade, hilt, and "features" of the blade, as well as the materials needed for them. Let's say I was building a fairly unique sword.
I'd take a design for the blade first. Let's say, Hammerhead, then choose a metal type that fits it, such as Steel. (Hammerhead is like FE:A's Armor Slayer, big, wide, and "hooked" like an anchor).
Then, I need a hilt. Choosing 2-Handed then the specific kind (we'll go with one that's longer than average, for easier control.)
Then, the base cost is tallied. From there, features can be added- these affect the blade in some way, and stack, but add costs especially when using more than one. Let's say I've got a lot of coin and can take three of them on the sword.
Taking something like Hollow Center allows me to reduce durability a bit to also greatly reduce the weight. From there, I'll add Poison Drip using the space freed up on the blade, allowing for a poison bottle to be affixed to the blade for a little extra weight. Lastly, I'll throw in a Serrated Edge for extra crit damage- all of which, singularly, dosen't cost too much, but as each extra feature increases cost exponentially, will be a very valuable sword.
Since it's built for two hands, and still quite heavy, I'll give it to one of my heavier units. He's already adorned with heavy layers of armor, and is now battle ready.
In combat, the heavy unit moves slowly but is able to take a great many hits, sometimes without even taking damage- the many layers of armor and large helmet make arrows nearly useless, and anything that gets close is cleaved in two with the sword. The Hammerhead is good versus armor, such as the armor on it's wielder, so even heavy spearmen have trouble getting in close. I don't have any range, however, and magic is still very much a problem. Any stray fireball or gust, and I'd likely be screwed.
Classes aren't really present, but characters are built differently. Size and strength, for instance, as well as inteligence and speed, go into a character- a large character won't always make a good thief, whereas a small character can't use large weapons effectively. Races can mitigate this somewhat (Dwarves can use 2H weapons, for instance).
Multiplayer is set up so that each player gets a set number of soldiers and gold. Each player may not deviate from soldier amount, unless a range is given, and each unit must pass a basic equipment test (a unit without armor or weapon cannot be used.) Let's say I'm playing a 5 vs 5 match. 15 different soldiers are randomly generated, then I must pick five and outfit them how I see fit.
Attack animations are affected by many things- skills, events before the attack, who's against what, etc.
If I have an Archer who moves up near a target before firing, it might show him sliding across the ground while drawing the bow then firing. However, if they used a skill for accuracy, it might show them running ahead, drawing while moving, then stopping to aim.
A sort of relationship system would also be included, for the story and possibly multiplayer. Fighting together builds relationships- say that I have the Hammerhead-wielding heavy fight alongside a much smaller but agile mage able to keep the threat of magic away for a while, and they both survive for long enough to build a good friendship.
Once a certain threshold is passed, both units can be "retired" (no longer available to fight, they give their things back as well as some kind of boon) and in a mission or two, or after a certain amount of time, their child or children can fight with you. In this case, I'd wind up with something between the two I put in- a midweight capable of using two-handed weapons as well as magic, sacrificing the superheavy armor as well as some agility. This could have resulted any way- I could have had a tank that could only use magic, or a lightweight somehow able to throw a giant sword around, depending on what was passed down and what wasn't.
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World of Warcraft, if some servers allowed player races to become extinct via permadeath.
This wouldn't work as in order to make certain species go extinct in a game you'll have to exterminate both player characters and non-player characters, which would break certain quests and various functions. That and the necessity for at least non-player characters if not player characters to breed and have children would make it like World of Warcraft meets The Sims. That might work but it would be really messy and it would lead to a lot of newbies quitting the game outright.
Not if the "breeding" aspect isn't played in any fashion and the quests are handed out by deities. Possibly have it so that if all warriors are wiped out, that race "loses favor" of their patron god, and is doomed to extinction.