Also potentially interested, based on plot/era. Not too fond of the Korra stuff, personally, but if you wanted you could look up the franchise's TTRPG stuff; they have a lot of good suggestions for campaigns in different eras of the setting.

I've always wanted to make an old, crotchety Earthbender kung-fu-master-archetype; the kind that's gotten old enough he can't do much of the flashy stuff anymore, but makes up for it with precision/ruthlessness. Like, another earthbender is getting ready to do their big stomp so they can throw a boulder at him---the old man kinda pokes his toe in the ground and a nail-shaped spike comes up right underneath where the opponent's foot is going to come down. Cue their reaction. But would a "been everywhere, done all that, killed a lot of people in my day" character be permissible in this RP, or do you think they'd come across as too OP?

Potentially interested, depending on what the plot is

Also potentially interested, based on plot/era. Not too fond of the Korra stuff, personally, but if you wanted you could look up the franchise's TTRPG stuff; they have a lot of good suggestions for campaigns in different eras of the setting.

I've always wanted to make an old, crotchety Earthbender kung-fu-master-archetype; the kind that's gotten old enough he can't do much of the flashy stuff anymore, but makes up for it with precision/ruthlessness. Like, another earthbender is getting ready to do their big stomp so they can throw a boulder at him---the old man kinda pokes his toe in the ground and a nail-shaped spike comes up right underneath where the opponent's foot is going to come down. Cue their reaction. But would a "been everywhere, done all that, killed a lot of people in my day" character be permissible in this RP, or do you think they'd come across as too OP?

Also what were your qualms with Korra? Character focused or world focused? NGL I like that one too but feel like all the characters were way weaker in depth than the ATLA, but I really enjoyed the ideas behind the world-building and some of the places they took things.

I was thinking of two ideas, one being that the fire nation wins perhaps? Maybe a rebellion story?
OOOrrrr maybe they win but lose? Devastate the Earth Kingdom with Sozin's comet and awaken a sleeping beast as the Earth Kingdom as a whole pivots and becomes a brutal force to be reckoned with, even going as far as to completely flip the script and become the would be conquerors.

I'm not married to any of these ideas in particular, just spit-balling so far.

Or possibly something set after the war but before Korra's time, since it might allow people a bit more freedom with what characters they make (i.e. non-evil Fire benders). Something that takes place after a war no one thought was going to end, at least not so suddenly, at a time when things are starting to change drastically; nations reaching out to each other more, the Avatar returning, the beginnings of an industrial revolution and I think the comics talked about more and more spirits abandoning the human world?

My recommendation would be to keep it small at least at the start---instead of our characters being part of some rebellion against the Fire Lord, for instance, maybe give us a Seven Samurai-esque scenario where we're trying to set a village free from a relatively low-ranking Fire Nation army-captain who has basically been made a provisional governor or something. Or defend a crumbling temple where a scant few Air Nomads have somehow escaped the Fire Lord's genocide, but their commitment to pacifism makes them a sitting duck to the soldiers hunting them down. Bring down a bandit gang led by a brutal Earthbender, or some Waterbending Pirates harassing a group of refugees on their way to Ba Sing Se via ship. So on and so forth.

Or possibly something set after the war but before Korra's time, since it might allow people a bit more freedom with what characters they make (i.e. non-evil Fire benders). Something that takes place after a war no one thought was going to end, at least not so suddenly, at a time when things are starting to change drastically; nations reaching out to each other more, the Avatar returning, the beginnings of an industrial revolution and I think the comics talked about more and more spirits abandoning the human world?

Glad to hear you're doing well!

I think the choice of story/setting will ultimately have to depend on what you as the GM want to accomplish/see through this RP. These questions aren't really something you have to respond to here, but just to consider: What is it about the Avatar world that's got you hyped to run the RP? Are you looking forward to descriptions of bending battles and that distinct Wuxia flavor? Or was there some aspect of the Avatar universe's storytelling or world that you really want to immerse yourself and the players in? For instance, did you find a lot of meaning in the emphasis the series puts on character development (every member of the main cast except arguably Toph changes significantly either in their own perception, or in how we the viewers perceive them, from who they were at their introduction)? Or did you really love exploring the fantastical landscapes within the world---the Earthbending rollercoasters in Omashu, the Three Walls of Ba Sing Se, the icy fortress of the Northern Water Tribe, etc?

Which of those things you want to put in front of the players, and in which proportions, should determine your bare-bones plot structure. If you want world-building, you'll need to implement a "journey" of some kind so that we travel a lot. If you just want high octane action, you might want to give more thought to the enemies we'll be facing, how they're organized, and how to make the Players want to kick their faces in.

Then, the rest of this is just my own personal opinion---feel free to ignore it if it's not conducive to your own GMing style:

Building RP Plot [+]

The meat of the plot itself should be adaptable enough that you can tie it into your character cast and link up their backstories. For instance, if somebody made a character whose parents were killed by Firebenders, then maybe the Firebender who did it needs to be an underling of your Big Bad OR the Players need to HELP a village of innocent, second-generation Fire Nation Colonists against cruel Earthbending Bandits---both scenarios force that Player Character to deal with the trauma of their past in some way.

Another example: If someone makes a character who's struggling with the morality of using Bending Arts to kill, then maybe you make a recurring antagonist who's a sadistic assassin despite having no Bending Arts of their own, so that when the Players clash with them it can give the struggling character a means to further their development.

Beyond direct character contrasts between Players and NPCs, though, you should also try to build off what Players give you in their Character Backstories. If one Player makes an Air Bending Thief, for instance, and in their backstory they talk about how they got kicked out of their Air Temple and turned to a life of crime, whereas another Player makes a Non-Bending Bounty Hunter who's a Master Swordsman, then maybe you should DM the two Players and see if they'd be willing to establish a link between their characters that can effect the roleplaying and team dynamics---Maybe the Bounty Hunter once caught the Air Thief, but after being turned in to the authorities the Thief had to take some desperate measures to break out, like breaking the one Air Bending tenet of non-lethality they still valued. Now that death still haunts them. Or maybe the Thief stole a family trinket that was very important to the Bounty Hunter, and ended up selling it, so now the Bounty Hunter can't kill them/take them in until they find out where/to whom the heirloom was sold.

Similar strategies to tie your plot and world building elements to your Players not only keeps them invested in your game, but can give you a jumping off point as a DM. It's so much easier to come up with ideas for how to move a story forward if you have elements you can use as a springboard, versus coming up with new stuff out of the blue whole cloth.

I might be interested in this. I had come up with a character that I was never able to use, so I'd like to use him here, but I want to make sure it's not too out of line.

He is an air nomad who started experimenting with sound as an aspect of air, developing his own form of bending. But he took it too far and was labeled an apostate for violating certain tenets.

Great advice, although I was looking to have a more collaborative and less hands on approach for this, but I think I might pivot. It's been years since I've ran an RP so I gotta shake the rust off the chains.

I'd love to hear more about this. Have you read any of the Chronicles of the Avatar books? I haven't myself but I was doing a bit of research on the concept of soundbending after you mentioned it and it's something that apparently avatar Yangchen might have developed well before Aang's era even. My only concern basically is how the whole apostate thing comes about, admittedly I don't know enough on air nomad lore myself.

<Snipped quote by TaintedMushroom>

By that, do you mean you'd want Players to come up with the plot elements, design antagonist characters, or something else along those lines? If that's the case, you could make a list of things you'd want Player input on, or just ask them the same questions I pointed out before--"What do you want to see in this RP?" basically, but maybe more specific.

Do you have a Character Sheet drafted yet? For a collaborative plot, knowing what kind of characters you'd be looking at would probably help a lot. Like I mentioned before, getting characters to tie their backstories to each other or to other elements of the RP has, in my experienced, helped a lot.