At San Diego Comic Con, the creators of the show mentioned that Book 4 will most likely be the final chapter of the Avatar Universe. Also the rest of Book 3's episodes will be moving online. Reason being that apparently ratings are far higher on the internet than it is on TV, so it's not being cancelled any time soon. HOWEVER it is a strong possibility that Book 4 of the series will be the last we see of the Avatar Universe. They also stated that this COULD be their last appearance at Comic Con. So yeah, Book 4 is probably the last we'll see of NEW content as far as Avatar is concerned.

Yeah, I think most fans assumed Book Four would be the last, at least in the LoK series. I think what fans were really worried about was whether or not we'd even get a Book 4 at all. As long as the series is ended properly, with the characters and storylines getting the appropriate closure they deserve, I don't think we'll have any issues.

Some have said we could see MORE spin-offs down the road...... But really with this kind of creative team, I honestly wouldn't say it was out of the realm of possibility. Originally it was thought they'd never do anything past Avatar: The Last Airbender, so whether or not they choose to do another series I believe is still a possibility.

Personally I wouldn't mind them doing a prequel series, possibly following the adventures of an Avatar set before ATLA. But when it comes to a show like this, I'd only want to see another series so long as the original creators are up for it. If they feel like they want to move on, I think that's completely reasonable and wouldn't really be upset about. But if they feel there's another story they want to tell in this amazing world they've created, I'd love to see what they can come up with.

After all with the reincarnation concept I'd say that the show has the potential to run for as long as ANOTHER series of which I am a major fan

[youtube=www.youtube.com/watch?v=4_-vQ8n77Rs]

3477748 Well, ATLA ended in Book 3 so it's not a shocker if LoK ends too, but it would be great if it does get a fourth season, eh. Now, as with the spin-off series I think they should do a prequel, but about what, eh? The Hundred Year War sounds like a pretty good place to put a new series in, eh.

3477979 Well we also have 10,000 years worth of Avatar's to go over. I wouldn't mind seeing Wan's immediate successor who TRULY starts the Avatar lineage as the 2nd Avatar.

3477983 When I really think about it I would actually like to see a full scale, world war during the Hundred Year War, eh.

3478003 Yeah but how would that work with no Avatar? I'd see that as more of a comic series or something.

3478050 But what about Avatar Roku, eh? He was a fire nation-born Avatar after Kyoshi, but before Aang, eh. Sure, he died before the Hundred Year War, but it could be a series about his path that led to his death, preventing him from stopping a war. It could be like a single season type of thing, but it would be great to see how the war started from.

But, we kinda know what his journey is all about so there's not a lot of reason for him to have his own series, eh.

3478095 This is the better compromise of that.

3477748 I do hope Nick will at least put the episodes back on T.V. for those who want to watch them. They could always bump it to their Nicktoons block if they really wanted, Nicktoons already broadcasts re-runs of The Last Airbender, sometimes with the DVD trivia included.

3477748 If Korra does end at Book 4, I hope it gets a good sendoff at least.

As for future projects, past Avatars are a goldmine of possibilities (if they decide to do more, which I hope they do). Personally I would want to see more Kyoshi or Wan, but even a completely new Avatar that we've never met might be interesting