On the topic of my "OCs being formerly Len'en fan-characters"; let me provide a bit more detail, even if it is very cringe + some "modern" changes. Take it as an AU where the characters of "TatariGatari" didn't suffer from a curse and paranoia and were just a bunch of bumbling idiots It used to have even a name, but it was hilariously dumb and verbose on the English side and extremely basic on the Japanese side, so let me omit that info, but it was a Len'en "fan-game"
By a string of various "random" occurrences, three people received washed up letters that asked for help to exterminate a deadly tree that has been terrorising a certain island located somewhere on Gloomy Strait, and it said that holding onto that letter will eventually help them find the mysterious island. It also promised a "luxurious" reward for exterminating the said tree. Those three were Tsubakura, via Yabusame fishing up a letter; Kuroji, via Aoji going on a stroll by the sea; and Kunimitsu, via Medias receiving the letter during patrol. It said that only ONE person can access the island and the visitor SHOULD NOT bring their companions to the island, as the letter won't work.
And after they arrive, the letter tells them to go towards the highest point of the island, there they will receive the directions of the tree Yep, this story was pretty much a commission from some random hobos from a remote island
On the first stage, our heroes encounter a brush Tsukumogami "Yasuke" (their previous name was "Sagakuro no Itsumo", but it was dumb) and make quick work of them.
Reaching the entry gates of Wadano Shrine, they meet "Wadano no Tenmuyonji" (previously "Tenmuyonji Kaibutsu", but who tf has a surname that literally means "Monster"?) who tells them how to reach the accursed tree... After attempting to kill them of course, so they could deal with that matter themselves as they're bound to the shrine (thus cursing the guests into being the next "Wadano no Tenmuyonji"). Beforehand they cursed the guests into hearing the dead so they could communicate, and as a punishment condition if they fail to exterminate the tree
After being given the directions, the guests stumble onto the food court where they meet Osen, a sea bunny slug who is currently a shikigami/servant of a deity of this island and is honorary subordinate to the next boss. They were thrown out of the loop, only hearing that the guest will come over; and since guests in Osen's peanut-sized mind are bad news - they pretty much ruined one of those "rewards" by spiking everything with lethal poison. Tsubakura hijinks ensue and Osen tries to deal with the guests, only to be punted away and the guests fly towards the forest
Osen tries to take revenge this time, saying that they'll protect someone else, but Osen is weakened by then and they are again punted away. The guests get lost and the person who sent the letters in the first place makes an appearance. Shinzou Amanojaku, halfhuman and half-amanojaku whose ability makes it possible to make wishes come true in one shape or form. They sent three letters in hopes of finding a moderately strong exterminator who would want to chop down a tree and at first glance they were heavily disappointed (especially by Tsubakura, since they thought they were going to summon Tsurubami; to others they say that they regret calling upon someone way weaker than Senri Shrine priest), so they challenge our guests to battle, to see if they're truly worth the effort of summoning onto this accursed island. After the battle they half-heartedly acknowledge the strength of our guests (unfortunately for everyone, Shinzou has a high tolerance of pain, that's why they're a horrid judge of strength) and lead the way from the endless forest. They also ask our guests to "break the bones of the chain smoker" and wish them luck
Finally guests arrive at the foggy clearance and they encounter Yasuke yet again. Beating the brush for the second time, they encounter Sunao Fujisaki (previously it was Sunawa Naoshita(?); but it was a very lame name with dumb meanings) - who while in the current state they're a mere former citizen of Devangara who fled after the "Emperor's Massacre" occurred (thus they're particularly terrified of Kunimitsu). They just fled from the tree, telling our heroes to not come any closer if they value their lives, but they get promptly ignored and beat up
Soon our heroes come to the battlefield where various ghosts start to attack them. It seems like they're trying to prevent the incident from being resolved. After weathering through the onslaught of unnamed soldiers, heroes face the five elite soldiers from different fractions. First was inhabiting their Tachi; the Second was inhabiting a pair of chained Kama; the Third was inhabiting a kettle; Fourth was inhabiting Ono and the Fifth was inhabiting a Tonfa. These five were NOT friends with each other, in fact they were bitter enemies, and were heavily inconvenienced by the bloodsucking tree defiling their corpses, but they grouped up because the protagonists came by Tenmuyonji's request, their common enemy. They got beat however, and they're in awe with the current patterns from the "spell card era of battle". While the spell card system was introduced a long time ago, it was only a recent development on this island. And so, our protagonists arrive at the centre of the incident. There was a large bloodsucking tree and soon it began to speak. "Are you the next challenger, huh?" It was supposed to be mindless, but a powerful yokai, but it committed a mistake of sucking the blood of the most powerful general on the battlefield, as such it had lost complete agency, and now the general, Hanegawa no Koryuu (羽根川の湖流), is in control of that body due to his strong, yet vengeful spirit. As a bloodsucking tree, he can't help BUT to suck the blood of the fallen soldiers, but he got an idea that once he'll suck this land dry, he'll be powerful enough to move, and thus, finally bring the end to Tenmuyonji. And since the heroes were sent by Tenmuyonji, he will make sure they'll die a slow, painful death. Of course, since this is our protagonists that we're talking about, so they beat the crap out of Jubokko symbiote and the spirit escapes.
They chop down the tree and Tenmuyonji (along with Shinzou for transportation) congratulates them on fulfilling their request. They told our heroes that the wood from Jubokko IS a luxurious reward they promised and they, disappointed, carry the wood back to their home. Tsubakura decides to have a small sample size in their laboratory, while the rest is used for firewood (there was a side game where Yabusame, Saragimaru and Medias solve another incident that is related to this game). Kuroji uses it to make expensive medicine. And Kunimitsu gives it to Yago to make a new blade from it (doubt they would use it, as they like their Bankuruwase more, but it is pretty much the miniature reverse of Rudhira).
Extra is about our heroes wanting to make contact with that island, but Wadanojin comes in and tells them to fuck off and initiates a battle where he uses tide jewels to boost his danmaku cards, as he's quite weak unfortunately (weaker than Tenmuyonji); so weak that he summoned his subordinates to fight later on. They beat him, but then Shen appears to tell them the final "fuck off" signal (and our heroes realise that it was them that Shinzou told them to fuck up) and then another battle begins, but now they're doing it solo and no boosters. They get defeated, but thanks to their powers of illusion, they do a smoke screen and the island disappears (oh, and Akasa is alive in this timeline), but not before thanking them for killing that awful tree as it was also sucking the blood of their beloved friend.
Fun fact, Shen, or at least their prototype, was supposed to be a 4th boss and back then they were just a reporter looking for a scoop. Yep, that's it. And yes, Shen is pretty much inspired by Kasumi Shindou and some other character that is a huge spoiler for a certain Ghost game and some other spoiler character from a certain Detective game