OOC: Ramble
(Note: I'm using lyric translations from here for the sake of essaying because it's convenient since there's translations of all of the songs there, but Gackt's lyrics tend to be really layered and hard to translate so I'm working on understanding them for myself, and collecting every translation I see)
Kei's Canon
While the movie Moon Child can stand on its own, it's actually part of a larger work known as the MOON Project, which is purely Gackt's baby. This means that Kei's canon officially includes (so far at least) the movie, a novel, three full albums and their respective concert tours, many interviews, and a line of silver jewellery. That's not spin-offs, or merchandise or anything, that's actual sources of information about the world and story. Luckily, most of it is pretty irrelevant to Kei as a character.
As far as we know, and this is from translated interviews that I've forgotten the location of so I'm going by memory, the storyline of MOON takes place from about 700 AD until a little way into the future. This is broken up into four parts, making the plot of Moon Child at least part of the fourth part. Now, Gackt being Gackt he decided to start with the fourth part, and so far he's only done that and a bit that he says is between the first and second parts. No one knows if he'll ever finish it, or explain any of it. So far Moon Child is the only really coherent look at it we've gotten -_-
ETA: I found the interview that explains it all, it's here.
So then, the fourth part of MOON is generally accepted to include the movie, the novel and the albums Moon and Crescent. I'm not really sure where the tours fit in, and I haven't actually seen the one that's most likely to be relevant so I'm waiting until then to guess. My personal theory is that the album Moon actually contains snippets from the entire saga, rather than just the fourth part, but that still means it has relevant parts. Crescent does seem to be firmly based in the characters of the movie. As far as I'm aware, the novel is based on Son, who's one of the main characters in the movie but whose life doesn't intersect with Kei for quite some time. That means I'm not too fussed about it either, which is good because I don't think it's been translated.
What I'm taking as canon outside of the movie
Basically, the main thing I'm taking as extra canon is Crescent. We have no sure way of knowing just whose point of view all the songs are from and who they're about, but I can make some fairly educated guesses. In particular, I believe that Hoshi no Suna is from Kei's point of view, and is probably from during the first timeskip, after he watched his mentor Luka kill himself in the morning sun. Luka taught Kei the song Orenji no Taiyou, which Kei then later taught to Sho, meaning that any song which mentions "the song you taught me" or similar is probably Sho talking about Kei or Kei talking about Luka. And Sho has never been alone like Kei has, hence this song being Kei's point of view. What this means is that Kei was in love with Luka, which is really my rather complicated way of saying that Kei canonically loves men. Or male vampires. Whatever.
It would be nice and symmetrical to say that Tsuki no Uta is Sho's point of view about Kei, especially since Hoshi no Suna was released as the B-side to the Tsuki no Uta single, but I'm not nearly so sure of that, and of course that'd be up to whoever hypothetically apps Sho.
I also really, really want to say that Last Song is from Kei about Sho during the second timeskip, ie when I've taken him into camp from. It has that whole mindset that Kei can't go back because he'd only screw things up for everyone else, and he knows that Sho loves Yi-che and should be with her. It seems really flowery, but then this is Gackt writing a major single, so it's probably better to just ignore a lot of the floweriness because I know he writes his singles to be more generic and then puts the good songs on the B-side.
Basically, this is justification for the way I interpret the love triangle in the movie, outside of what seems apparent from the way the characters act in the movie itself. We know that Yi-che loves Kei far more than Sho, and we know that Sho loves Yi-che enough to badger her into marrying him, but I think that Kei loves Sho and never loved Yi-che at all, although he did like her well enough.
The rest of the songs on Crescent express things that are pretty easy to read into the characters anyway, I think.
What about all that other stuff that technically makes up his canon?
Most of the rest of what currently makes up the MOON project is concerned with a time around 1540 AD, when the vampires were first created. We do have a reasonable idea of the storyline based on a couple of interviews and the Diabolos concert, but not nearly as clear as Kei's storyline in the movie. The only thing I can think of that might affect Kei is the clans that were introduced through the H-Darts jewellery, but, well, everything we know about the clans so far comes from the jewellery and that's not much. I'm not even sure how the clans affect the vampires since they're clans of Darts, which is short for Darkside Inhabitants. I think that the storyline goes that the Darts were warring with each other and one faction created a bunch of vampires to fight for them. Which would logically mean that all vampires belong to that clan, but I've no idea which one it is, or what Darts are meant to be exactly, or if they're still meant to exist, and either way it's probably entirely irrelevent to Kei and I mostly wanted an excuse to ramble about the fact that everything we know about this comes from a line of silver jewellery.
Kei's age
I think it's fairly reasonable to say that Kei is not very old for a vampire. It actually really bugs me in reviews of the movie when they criticise him for not coming across as a creature who's lived through centuries, because I really don't think he has. Luka seems to have been the one who turned him into a vampire, and it doesn't seem like he'd been a vampire for very long when Luka died. I'm extrapolating this from Kei's distress when Luka said he was giving up (maybe Luka turned Kei in a last-ditch attempt to keep himself interested in living), and the fact that he doesn't want to or seem to be able to find himself a new companion. Clearly he's never been with anyone but Luka, and we know that he doesn't seem to survive longer than a decade or so by himself. There isn't any direct canon evidence that he wasn't with Luka for a very long time, but it seems far more like a mentor-student relationship than it would be if they'd lived centuries together.
So, let's arbitrarily say that Kei was with Luka for 5 years. If Kei was turned when he was 21, that puts him at 26 when Luka dies. Then there's the first timeskip, making him 40 when he meets Sho. The timeskip as Sho grows up puts him at 51. It's unclear how long the next part of the movie takes place over, but it can't be more than a month or two since Kei isn't drinking blood the whole time. So he'd still be 51 when he leaves, and since I'm thinking it may have taken a year or so for him to hear about and make his way over to America and camp, that puts him at around 52. I'm going to have him be reticent about his age as much as possible anyway, since that time he was with Luka really is a wildcard and it might just officially come up sometime.
Kei's Canon
While the movie Moon Child can stand on its own, it's actually part of a larger work known as the MOON Project, which is purely Gackt's baby. This means that Kei's canon officially includes (so far at least) the movie, a novel, three full albums and their respective concert tours, many interviews, and a line of silver jewellery. That's not spin-offs, or merchandise or anything, that's actual sources of information about the world and story. Luckily, most of it is pretty irrelevant to Kei as a character.
As far as we know, and this is from translated interviews that I've forgotten the location of so I'm going by memory, the storyline of MOON takes place from about 700 AD until a little way into the future. This is broken up into four parts, making the plot of Moon Child at least part of the fourth part. Now, Gackt being Gackt he decided to start with the fourth part, and so far he's only done that and a bit that he says is between the first and second parts. No one knows if he'll ever finish it, or explain any of it. So far Moon Child is the only really coherent look at it we've gotten -_-
ETA: I found the interview that explains it all, it's here.
So then, the fourth part of MOON is generally accepted to include the movie, the novel and the albums Moon and Crescent. I'm not really sure where the tours fit in, and I haven't actually seen the one that's most likely to be relevant so I'm waiting until then to guess. My personal theory is that the album Moon actually contains snippets from the entire saga, rather than just the fourth part, but that still means it has relevant parts. Crescent does seem to be firmly based in the characters of the movie. As far as I'm aware, the novel is based on Son, who's one of the main characters in the movie but whose life doesn't intersect with Kei for quite some time. That means I'm not too fussed about it either, which is good because I don't think it's been translated.
What I'm taking as canon outside of the movie
Basically, the main thing I'm taking as extra canon is Crescent. We have no sure way of knowing just whose point of view all the songs are from and who they're about, but I can make some fairly educated guesses. In particular, I believe that Hoshi no Suna is from Kei's point of view, and is probably from during the first timeskip, after he watched his mentor Luka kill himself in the morning sun. Luka taught Kei the song Orenji no Taiyou, which Kei then later taught to Sho, meaning that any song which mentions "the song you taught me" or similar is probably Sho talking about Kei or Kei talking about Luka. And Sho has never been alone like Kei has, hence this song being Kei's point of view. What this means is that Kei was in love with Luka, which is really my rather complicated way of saying that Kei canonically loves men. Or male vampires. Whatever.
It would be nice and symmetrical to say that Tsuki no Uta is Sho's point of view about Kei, especially since Hoshi no Suna was released as the B-side to the Tsuki no Uta single, but I'm not nearly so sure of that, and of course that'd be up to whoever hypothetically apps Sho.
I also really, really want to say that Last Song is from Kei about Sho during the second timeskip, ie when I've taken him into camp from. It has that whole mindset that Kei can't go back because he'd only screw things up for everyone else, and he knows that Sho loves Yi-che and should be with her. It seems really flowery, but then this is Gackt writing a major single, so it's probably better to just ignore a lot of the floweriness because I know he writes his singles to be more generic and then puts the good songs on the B-side.
Basically, this is justification for the way I interpret the love triangle in the movie, outside of what seems apparent from the way the characters act in the movie itself. We know that Yi-che loves Kei far more than Sho, and we know that Sho loves Yi-che enough to badger her into marrying him, but I think that Kei loves Sho and never loved Yi-che at all, although he did like her well enough.
The rest of the songs on Crescent express things that are pretty easy to read into the characters anyway, I think.
What about all that other stuff that technically makes up his canon?
Most of the rest of what currently makes up the MOON project is concerned with a time around 1540 AD, when the vampires were first created. We do have a reasonable idea of the storyline based on a couple of interviews and the Diabolos concert, but not nearly as clear as Kei's storyline in the movie. The only thing I can think of that might affect Kei is the clans that were introduced through the H-Darts jewellery, but, well, everything we know about the clans so far comes from the jewellery and that's not much. I'm not even sure how the clans affect the vampires since they're clans of Darts, which is short for Darkside Inhabitants. I think that the storyline goes that the Darts were warring with each other and one faction created a bunch of vampires to fight for them. Which would logically mean that all vampires belong to that clan, but I've no idea which one it is, or what Darts are meant to be exactly, or if they're still meant to exist, and either way it's probably entirely irrelevent to Kei and I mostly wanted an excuse to ramble about the fact that everything we know about this comes from a line of silver jewellery.
Kei's age
I think it's fairly reasonable to say that Kei is not very old for a vampire. It actually really bugs me in reviews of the movie when they criticise him for not coming across as a creature who's lived through centuries, because I really don't think he has. Luka seems to have been the one who turned him into a vampire, and it doesn't seem like he'd been a vampire for very long when Luka died. I'm extrapolating this from Kei's distress when Luka said he was giving up (maybe Luka turned Kei in a last-ditch attempt to keep himself interested in living), and the fact that he doesn't want to or seem to be able to find himself a new companion. Clearly he's never been with anyone but Luka, and we know that he doesn't seem to survive longer than a decade or so by himself. There isn't any direct canon evidence that he wasn't with Luka for a very long time, but it seems far more like a mentor-student relationship than it would be if they'd lived centuries together.
So, let's arbitrarily say that Kei was with Luka for 5 years. If Kei was turned when he was 21, that puts him at 26 when Luka dies. Then there's the first timeskip, making him 40 when he meets Sho. The timeskip as Sho grows up puts him at 51. It's unclear how long the next part of the movie takes place over, but it can't be more than a month or two since Kei isn't drinking blood the whole time. So he'd still be 51 when he leaves, and since I'm thinking it may have taken a year or so for him to hear about and make his way over to America and camp, that puts him at around 52. I'm going to have him be reticent about his age as much as possible anyway, since that time he was with Luka really is a wildcard and it might just officially come up sometime.