Most of this information is taken from a tumblr news post that has sources, however I will be paraphrasing, but to give credit, this the original source.
Update 1: Added new information
Update 2: Added old information
Update 3: RELEASE DATE!!
Update 4: Added info about Hiroshi Sato per Cybit's comment
Update 5: Added new info about Korra/removing disproved speculation.
Update 6: New Clip
Update 7: Trailer
Update 8: Details + Adding Video Section
Book Four Confirmed Information[]
NOTE: Before continuing I'm going to tell you there are links to videos in a separate; these contain information not mentioned in the Details section
Basic Information[]
Book four is called balance, [1], and it will be 13 episodes long and animated by Studio Mir. The new villain has no direct tie to the Red Lotus,[2], and the final book will air on Friday October 3rd[3].
Details[]
- We know that Jason Isaacs is returning, although that was later deleted. However, that doesn't make this tweet any less real, Grey DeLisle's posts about returning to Book 2 and 3 were deleted, even though she did return, and April Stewart's later deleted tweets about joining the Korra cast for Book 2 were true.this
- Per the same tweet, Isaacs's character, Suyin Beifong's VA, Huan's VA and Jinora's VA have a scene together, likely as these characters.
- Korra will definitely have at least a few fight scenes, although I suppose that doesn't really need confirmation. [4]
- Korra and Katara have at least one scene together [5]
- The airbenders are working to keep peace as a "Jedi-Knight like role" [6]
- Per the above source, Book 4 ties into Book 3
- New footage has dropped, as nickelodeon accidentally included Book 4 footage in a trailer about Book 3 airing on television for the first time. In it, Kuvira stands looking very sinister, and in a different part of the trailer looks as if she's about to be attacked. [7]
- Some animatic sketches from Book 4 here and here.[8]
- Episode 4 is called "The Calling"[9]
- Hiroshi Sato will return[10]
- Korra has a new hair cut. [11]
- New clip from Book 4! [12]
- One episode dedicated to Korra's recovery.[13]
- Varrick talks about his childhood in one episode.[14]
Videos[]
Speculation[]
None of this information has any official confirmation, but is based on fan theories!
- Since Book 1 was about Korra learning to airbend, Book 2 was about the Water Tribes conflict, and a large amount of Book 3 took place in the Earth Kingdom, fans speculate that Book 4 will take place or have to deal with the Fire Nation. This would match up with Zuko's sudden appearance at Book 3 and suggests he may play a part in Book 4.
- Since Kuvira was name dropped in the finale, and in addition to the new footage, it is possible if not likely she may play a villain in Book 4.
Conclusion[]
We know a little bit about Book 4. It isn't nothing, but we can begin to start speculating about what's going on, since we do have a few pieces of the puzzle.