If there's one thing that irritates me, it's when people think that Kingdom Hearts 1 and 2 are somehow more important than the rest of the games in the series. Even people who realize that every single game in the Kingdom Hearts series has essential information seem to think that all of the non-numbered games are still not as important as the numbered games. So, I decided to give my take on how important all of the KH games are to the overall story and how essential they all are in order to understand what is happening in Kingdom Hearts III.
I divided the games into two groups: Games that are extremely important to understanding the overall story and games that are less important.
Extremely Important Games
1. Kingdom Hearts
2. Kingdom Hearts Chain of Memories
3. Kingdom Hearts II
4. Kingdom Hearts Birth by Sleep
5. Kingdom Hearts [Dream Drop Distance]
Less Important Games
1. Kingdom Hearts 358/2 Days
2. Kingdom Hearts Re:coded
3. Kingdom Hearts Union χ[Cross]/Kingdom Hearts χ Back Cover
4. Kingdom Hearts 0.2 Birth by Sleep -A fragmentary passage-
Many people mistakenly think that Kingdom Hearts II is the sequel to Kingdom Hearts 1. However, Chain of Memories is the sequel to Kingdom Hearts 1. Kingdom Hearts II is the sequel to Chain of Memories. Now, Chain of Memories isn't necessarily needed in order to understand Kingdom Hearts III (other than maybe having to know about Riku Replica, Marluxia, and Larxene), but Kingdom Hearts II is, and if you skip Chain of Memories, you won't know what's going on in Kingdom Hearts II.
Birth by Sleep is extremely important because it introduces us to Terra, Aqua, Ventus, Vanitas, and Master Xehanort. All of these characters are extremely important to Kingdom Hearts III. I mean, Master Xehanort is the main antagonist! It also shows us the fates of all of these characters, which we will need to know for Kingdom Hearts III. Not to mention, we find out what Master Xehanort's ultimate goal is in this game: to forge the χ-Blade and start a second Keyblade War (this isn't as important to know ahead of time since we probably will be told this in Kingdom Hearts III, but this is when we are introduced to his goal for the first time).
Dream Drop Distance is also extremely important because it literally sets up Kingdom Hearts III. It ties everything from the past games together (or at least it attempts to), informs us of what Master Xehanort's new plan to achieve his ultimate goal is, and leaves us with the heroes preparing for what to do next.
The remaining four games (five if you count Back Cover as its own thing) are still important but are less important than the other games since they only have a few things in each of them that are needed to understand the overall story. 358/2 Days is the most important out of all of them because Xion's story is the story of the game, and Xion is who you need to know about for Kingdom Hearts III (assuming she plays an important role in the game, that is). All you need to know about from Re:coded is that there are people tied to Sora who are waiting for him to save them (also that Maleficent and Pete are now after the Book of Prophecies, which you find out in a new cutscene added to Re:coded in KH 2.5, but this probably isn't as important since you will probably be told this in Kingdom Hearts III). It is unclear how much you need to know of Union χ[Cross]/Back Cover, but you definitely don't need to know everything. You at least need to know about the Book of Prophecies, the black box, and what was revealed about Master Xehanort's Keyblade (you may also need to know about the Foretellers since Young Xehanort mentions the "lost masters", who he says started the Keyblade War, to Young Eraqus in one of the first Kingdom Hearts III trailers). I don't know how much from 0.2 you need to know, but I assume that you will at least need to know that Riku and King Mickey are off on a mission to save Aqua from the Realm of Darkness, that Kairi is going to train with Lea, and that Sora, Donald, and Goofy are off to Olympus Coliseum so that Sora can learn from Hercules how to regain the strength that he lost (most of this will probably be told to you in Kingdom Hearts III, so I don't know how much of this you will actually need to know before you play Kingdom Hearts III).
So, that's my take on how important all of the games are to the overall story and to Kingdom Hearts III. While it is true that not all of the games hold the same level of importance as others, I think that many of them are more important than people make them out to be, especially Chain of Memories, Birth by Sleep, and Dream Drop Distance.
Edited by Dagesh Lene, 10 August 2018 - 06:59 PM.