Is Tsubakura a cruel, selfish Jerkass and Sociopathic Hero that cares about nothing beside their own welfare and enjoyment? Or are they lashing out at everyone because they were designated as the hero of a Crapsack World without their consent. Or they have been broken by Suzumi's constant pestering and the death of their mother to care anymore?
Shion - really a nice, sweet person who had the rotten luck of being born from a Eldritch Abomination flower born of evil spirits and cannot help being influenced by them, or a Karma Houdini who knew full well how much damage they were doing while infesting Mugenri with spirits and only did a HeelFace Turn in the end just because they want to consume souls scot-free? And their actions in Brilliant Pagoda or Haze Castle, is Shion doing a Kick the Dog? Or they're just Innocently Insensitive?
Saragimaru. Are they a Broken Bird type character, emotionally unstable from constantly being rejected by Yaorochi, and not willing to risk becoming attached to anybody else - with some Snark Knight thrown in?
Is Yaorochi merely The Stoic with no other noteworthy traits besides their obsession with the Tasouken, or are they more complex than that? If the latter, then does their stoic exterior conceal a socially awkward person or mask a much darker personality? RMI doesn't help, showing Yaorochi to be a Blood Knight who enjoys battles and cutting people a bit too much.
Tsurubami. Were they a power-hungry ruler who sought only their own benefit, or did they honestly believe that things would be better if they took over Mugenri, considering that is is portrayed as a Crapsack World? Or is it a bit of both?
Kuroji. A misunderstood grouch with simply a huge inferiority complex stemming from being inferior to their siblings and Tsubakura or a grade-A Jerkass that simply likes being an annoyance to everyone?
Word of God implies that they hated being a Muggle Born of Mages in the Outside World and loves living in Mugenri because they got powers and attention. Also, the series hints as Kuroji's route becomes a Protagonist Journey to Villain. Even Tenkai is worried that Tsurubami choose to spirit away Kuroji, who has potential to become villainous and is willing to treat Mugenri like their personal playground for the sake of hedonism. At the end of Reactivate Majestical Imperial, Saragimaru fears that Kuroji will eventually become Drunk with Power and cross the Moral Event Horizon. By the time of Brilliant Pagoda or Haze Castle, Saragimaru is probably right.
Angst Dissonance: Saragimaru's entire existence revolves around them being miserable. This is played for laughs in-series.
"Blind Idiot" Translation: The first ever translation patch (for the trial version of Brilliant Pagoda or Haze Castle) was riddled with this.
Complete Monster: Suzumi Kuzu is the the Big Bad and is feared by everyone. Their modus operandi is to make Tsubakura cross the Despair Event Horizon and have done many actions in the past to nearly kill Tsubakura and/or Yabusame. They even try to attack and kill the Shitodo Siblings because they think it would make Tsubakura feel even worse, and even manage to cost Hooaka an arm. They're responsible for causing the whole war in Brilliant Pagoda or Haze Castle, all just to lure out Tsubakura and kill them. To make matters worse, it's HEAVILY implied that they did something horrible to Tsurubami, the only one who could possibly even relieve Tsubakura and Yabusame of their duties and let them back into the outside world.
Come the SecretTeam routes added to each game, and some of Suzumi's monstrousness gets called into question, particularly as we get implications that Tsubakura did something to incur Suzumi's hatred, see one of their personalities object to Cold-Blooded Torture and killing and attacking bystanders, while the other personality, for all their bloodlust, entertains a desire to reconcile with the main cast. Even JynX himself says that it's a secret whether Suzumi is a villain or a hero.
Clause/Tenkai, due to them controlling some sort of space and being Extra bosses.
While it wasn't confirmed, in a 2019 Tweet JynX did imply that there was some story tie between Clause and Tenkai
Mitsumo/Souko, due to them being 1 stage bosses. And sometimes, Terumi/Souko too.
Suzumi/Kurohebi, likely due to their obsession towards Tsubakura. It's later revealed that Suzumi was involved in Kurohebi's creation and is basically their "mother", with Tsubakura being "the father". It doesn't help that Kurohebi resembles them.
Common mooks that fire lasers. These are aimed at you, and are fast, requiring quick reactions, frequently will be the single biggest thread to face in stage portions.
Pretty much anything during the Firing Power I/II/III, Immortality, and Dimensional Destruction random sub-events. The first increases the damage of enemy bullets (turning them purple or white), which pretty much destroy your whole barrier/health gauge (assuming you have no upgrades); the second (available on Hard and Unreal modes) makes enemies invulnerable; and the third destroys all your barrier bars (including reserve ones), leaving you defenseless. All can also happen during boss random encounters, making them way more dangerous or effectively making their attacks survival (non)-spells.
The series' creator and the Len'en Project itself can count as one. Originally JynX was mostly known for their work on teaser videos of Touhou PC-98 remakes, with Len'en considered mostly their side projects inspired by Touhou. Now the series is considered by many on par with the Touhou series, some even enjoying Len'en more.
The Adagumo siblings very quickly became one of the fan favorite characters, making their appearence as playable in Reactivate Majestical Imperial all the more felicific and their demotion in Brilliant Pagoda or Haze Castle all the more heartbreaking.
Clause gets this treatment too, despite appearing in only one game until Brilliant Pagoda or Haze Castle. It's gotten to the point where the fandom's love for Clause is a meme by itself.
Jinbei, ever since JynX has revealed their official design on their Twitter.
Kuroji Shitodos driving insecurities and inferiority complex makes them relatable and endearing to some players, who are willing to look past their amoral behavior and often hope for their redemption. JynX himself says that Kurojis scoundrel characterization is just an act.
Suzumi Kuzu has their share of fans despite being, you know, a violently unhinged reality-warper out to ruin someones life. Most of their fans either just like Memetic Psychopath characters, or like them distinctly for being mysterious and hilarious walking lore exposition, particularly in their playable routes.
Epileptic Trees: Why is Kurohebi so nice to Tsubakura and only towards them? Their spellcards and name imply that Tsubakura (already a Teen Genius) is in fact their creator.
Good Bad Bugs: Compared to Touhou, Len'en has more difficult spellcards and the patters are similar to Seihou. Luckily the playable characters have glitches that makes them insanely powerful under the right circumstances. Especially noticeable in Brilliant Pagoda or Haze Castle.
Iron Woobie: Saragimaru. How would you feel if your Aloof Big Sister who you happen to love and idealize literally does not acknowledge or recognize you?
It's Easy, So It Sucks!: Many skilled players argue that Len'en, with it's larger, slower bullets, less complex patterns, memorizable stage design that relies on easy-to-kill waves of enemies, and the existence of flashbombs, are much easier than Touhou or other Bullet Hell games. Whether or not the in-depth story and funny, interesting characters make up for it is a matter of taste and priorities.
In the Touhou series (which Len'en is heavily based of), the shrine maiden Reimu Hakurei, while preferring not to be bothered, really hates that she isn't recognized enough as a miko and doesn't get enough worshippers for her god at her shrine. If the situation with Tsurubami is to be believed, then the alternative is much, much worse.
Iyozane is obsessed with becoming successful and gaining a place in the emperor's castle, right? It's much sadder after it's revealed they're the first successor to the throne, but were forced to went into hiding after being killed by their sibling (who had just found out they were a bastard child and was killing all throne successors).
Kunimitsu is maybe too shocked to see Iyozane again in Brilliant Pagoda or Haze Castle. That's because they thought they were dead all that time!
Hilarious in Hindsight: In an interview, JynX mentions that Kuroji's reversing ability would be useful for flipping hamburgers. If you look in the Scoundrel Team's Haze Route from Brilliant pagoda or haze castle, it's canon.
Cha-chaExplanation A Running Gag derived from the infamous Woolseyism mentioned below. Tsurubami is now consistently associated with dancing, with "cha-cha" being used as a joke phrase or euphemism in association with them
IT'S A SENRI SHRINE CONSPIRACY.explanation Most likely a parody of "It's a Moriya Shrine conspiracy!" from the Touhou fandom
Kaoru? Who? Explanation Kaoru Kashiwagi's page on the Len'en wiki remained empty for a long time, leading to a recurring joke that no one actually remembers who they are. Made that much funnier when it's revealed that apparently Kaoru pissed off Suzumi - someone who manipulates memory - enough to want Kaoru dead.
Shion face/Fashion Show.Explanation Shion's boss portrait in Brilliant Pagoda or Haze castle was meant to look threatening. Instead, fans thought it looked derpy and silly, at best sassy, and one user edited a picture of the sprite with the phrase "[N]ow they come back for fashion show". The fact that the word "fashion" contains Shion's name did not escape players, who also took to photoshopping Shion's silly, weird face onto just about anything and everything.
BIG MISTAKE, DA!explanation A translation of one of Suzumi's lines from the Shrine Team's extra stage, which has become a meme and something of a catchphrase. Sometimes rendered as "BIG MISTAKE YO"
Arguably an Ascended Meme, as one of Suzumi's upgrades and their upgraded bomb are actually called "Big Mistake".
Heatman explanation On the day Len'en Discord server started playing Hunger Games Simulator, one user uploaded a game where every character image was Hooaka, and almost all tributes were named Hooaka, with a few exceptions. The users, especially the one who made the game, had a love of one particular tribute named Heatman. Ever since, Heatman is often brought up when someone mentions Hooaka or Hunger Games Simulator on the Len'en Discord.
The Last Spell phase versus Tasouken itself. As the battle grows progressively more intense, with the music following suit, there is a part where the player must graze continuously to survive, and the music becomes louder and more desperate. Then, it dies out to a slow, solemn melody as Tasouken quietly expires. Made especially awesome if the Spell is captured.
Sukune's final attack in Brilliant Pagoda or Haze Castle. It's a Humongous Mecha haniwa, for pete's sake!
Moral Event Horizon: If their actions during Brilliant Pagoda or Haze Castle weren't already enough, then Suzune admitting that they made their Batman Gambit against Tsubakura so convoluted was because it would be more fun for themself is what does it.
Using your bomb on a very spammy attack plays a rapid machine-gun-like sound while the bomb eats all the bullets and rewards you with huge points.
Narm: Shion's boss portrait in Brilliant Pagoda or Haze Castle is meant to look menacing however their sassy pose and rather silly looking face and expression makes them look much less threatening than the Eldritch Abomination they really are.
Sukune Katano. They fire off powerful homing shots, and boxes you into small areas with their attacks. They also add periodic shotgun-style blasts from their haniwas.
Lumen Celeritas. Be prepared to deal with a Wave Motion Gun that covers more than half of the screen, while you try to dodge the other bullets and homing lasers.
Adagumo no Yaorochi. Many people have great difficulty with them, especially with the curvy snake lasers. If you accidentally approach their Battle Aura, prepare to a Death by a Thousand Cuts. They also have the annoying gimmick of slashing the bullets so that they become annoyingly small. Then you get to the final attack...
Sese Kitsugai, for a stage 1 boss. While the difficulty of the game is gradually but steadily raised until their battle, they themself is a nasty difficulty spike. Half of their patterns require very fast reactions - they just throws some annoying bones with a large hitbox. But later, you have to deal with VERY tightly aimed streams of bullets/lasers AND more bones they randomly throw everywhere. Then EX-Sese returns for the Extra hidden stage...
Shion. They isn't content to just absorb all the souls you were recollecting during the whole game as a life-source. Trying to wall you, shooting aimed knifes and bullets at you from every conceivable direction all at once. And bombs cannot affect them and you just have to wait until time runs out.
Suzumi Kuzu is known for being a nightmare to defeat even for experts. While the difficulty of the game is gradually but steadily raised until their battle, they themself is a nasty difficulty spike. Half of their patterns require very fast reactions - they just throw some knives and bullets that appear and disappear, since you have to memorize the locations, Reisen-style. And since all of their patterns are speedy and need very good reflexes rather than good bullet trajectory reading, you will usually have to bomb in advance to avoid losing even more resources.
Yaorochi has a extremely powerful attacks and bomb, as well as immense and incredibly dense strong bullets.
Sese in Brilliant Pagoda or Haze Castle starts out with a pretty pathetic shot type, but jumps to being absolutely devastating once you have them reach 60% power. At 80% or 100%, they can pretty much end spellcards in seconds once they get close, to the point where often the boss doesn't even get to fire a bullet by the time their health gets destroyed! Sese was so overpowered that eventually a patch was released that gave bosses a period of invulnerability at the beginning of each spellcard.
Similarly, Hooaka also has a shot type that starts out weak, but it gradually becomes a gamebreaker as they reach full power.
They Copied It, So It Sucks!: For diehard Touhou fans who consider this series to be a blatant Touhou rip-off, despite JynX averting this with Brilliant Pagoda or Haze Castle.
What an Idiot!: At the end of the Extra+a stage of Brilliant Pagoda or Haze Castle, Suzumi is defeated.....and they don't think of frisk or immobilize them. Instead, the heroes start bragging about how Suzumi's mind powers won't work on them twice. Suzumi ends up pulling a I Surrender, Suckers and running away.
As more of the Mugenri society is revealed and it becomes clear just how screwed up everything is, one might feel sorry for the outsider humans for being thrown into a Crapsack World against their will.
Brilliant Pagoda or Haze Castle also reveals that Tsubakura has a Dark and Troubled Past. We don't know much about it except that they're an apathetic Teen Genius who lives in a Crapsack World building weapons, accidentally caused a nuclear blast, their mother has been dead for a while and Suzumi has been tormenting them for a long time (and it's implied that either Suzumi killed Tsuba's mom or she died at said nuclear blast). What makes this probably worse than anything is that Word of God reveals that Tsubakura will have it way worse in the sequel, now that Suzumi followed them to Mugenri in order to continue tormenting them. Poor Tsubakura...
Woolseyism: While there are a few natural cases recorded in fan translations due to some Japanese idioms being very difficult to translate back into English, the most famous one is actually an accidental case of it, present in Tsurubami Senri's dialogue during Yabusame's Extra Stage in Evanescent Existence. The original text has them say: "Shall we finish this quickly?" in opposition to the "Shall we do the cha-cha?" the translation over The Wiki Rule has been providing since the beginning. Despite this slight translation "error", this added a lot of character to Tsurubami for western fans, to the point where this particular line of theirs became a meme on its own, and even after the "error" was outed, fans have wholeheartedly accepted it as they find it too fitting with the name of their theme song, Eternal Dance Engine.
Brilliant Pagoda or Haze Castle, Secret Team Stage 6 vs Tsubakura. While not as memey as the above, one line here gained a bit of fame: in a conversation between Suzumi's personalities, after Hamee explains their plan to torture Tsubakura then kill them, Ardey responds with disgust. The line literally translates as "You'e sick". The translators rendered it for tone as: "You are beyond fucked."