(I'm sorry for this wall of text, it is indeed the last thing I've copied)
Alright, I have compiled a list of everything anyone would need to know to enter the Vocaloid fandom
Vocaloid (known as ボーカロイド/Bokaroido in Japanese) is a singing synthesizer software created by YAMAHA Corporation, it was released on January 15, 2004, and has more than 70 different characters, each with their own voicebanks.
Here are the 8 most popular Vocaloids
(in order from left to right: MEIKO, KAITO, Megpoid GUMI, Megurine Luka, Hatsune Miku, Kagamine Rin, Kagamine Len, and Kamui Gakupo)
There are a lot more but they're not as important
Other things about the Vocaloid characters:
Len and Rin are mirror images, commonly viewed as either twins or a couple, but neither are officially confirmed
Miku really likes her leeks
Len's hair resembles a bunch of bananas
Rin likes oranges, chopping off people's hands and hitting her mirror image with a steamroller
Kaito probably wants to marry ice cream but he can't because I ship him with Meiko
Gachapoid Ryuto is very, very hated
Miku is the most popular Vocaloid
Meiko is an alcoholic but we love her anyway
Kasane Teto is a UTAU, not a Vocaloid. Everyone gets that wrong at some point.
Neru and Haku aren't Vocaloids or UTAUs, they're Fanloids. Everyone gets that wrong too.
Spoiler - click to show.
Len always dies. Always. There's no escaping it.
In order to understand anything that happens in the fandom you have to know the following songs:
World Is Mine
Senbonzakura
Magnet
Daughter Of Evil/Servant Of Evil
Nyanyanyanyanyaa! (The Nyan Cat Song)
Levan Polka (Leekspin)
Echo
Black Rock Shooter
Electric Angel
The Disappearance of Hatsune Miku (DEAD END)
Tokyo Teddy Bear? (You don't have to know this one, it's just really good and it's pretty popular)
Fear Garden & Secrets Of Wysteria (if you wish to understand the horror side)
There's also Gigantic OTN but I've never actually heard it and from the things I've heard about it I can safely say that I don't want to hear it and that it should never be spoken of on this good, Christian server
Fun fact, the first song created with Vocaloid was released in 2003 using early prototypes of Kaito and Meiko, and it was called "Ano Subarashii Ai o Mo Ichido". (I have never heard it before)
And you have to recognize these songwriters, even if it's just the names:
Ryo/Supercell
Circus-P
YusukeKira
Crusher-P
Kikuo
Maretu
DECO*27
SteamPianist
Giga-P
Reol
(there's a lot of others that are considered important but I don't know them so they obviously aren't that important)
And these people:
JubyPhonic
Rachie
Dj-Jo
Things about Vocaloid songwriters:
Ryo/Supercell is considered the god of the fandom
Kikuo is a twisted freak and if he writes something happy you know he's not okay
We must all bow down to Circus-Senpai
YusukeKira is indeed a derpy chicken disguised as a songwriter. All hail the derpy chicken.
Giga-P and Reol tend to write some not-so-innocent songs
Crusher-P has been stuck in her family's television for years. Send help.
Circus-Senpai is a gamer, nerd, and fanboy with an amazing voice and I definitely don't stalk his YouTube and SoundCloud constantly because I'm not at all obsessive
Things about those other people:
JubyPhonic and Rachie are humans, known for singing English covers of nearly every Vocaloid song in existence
Dj-Jo is not a Vocaloid songwriter, but they cover anime theme songs with Vocaloids and remix them and they're really, really good at it.
Vocaloid memes are 90% garbage
https://ibb.co/album/iVqHva (an album of good, bad and meh memes that I hath compiled for example purposes)
Other things:
Obsessive Len and Kaito fangirls don't exist. We've abandoned them for embarrassing the entire fandom.
Same with the people who call Miku their waifu and obsess over her (UUUUUGGGHHHHH)
Vocaloid is not an anime, believe it or not (Everyone gets it confused, even DanTDM)
VSQ and VSQX are the names of Vocaloid files
Anyone can download and use Vocaloids, they just cost a lot of money so common alternatives are UTAU and SynthesizerV/SynthV.
…I've run out of things.