How about a isekaid (knows he is a demon because she read the manga but refuses to tell him) fem reader x yandere sebastian?
How Do You Know That?” | Isekai!Reader x Yandere!Sebastian (Canon Compliant) ✧
A/N:reader is transported into Black Butler, knows everything about Sebastian, but never admits it. I worked on this over the weekend but forget to publish. Hope you like it 🖤
You don’t remember how you got here.
One minute you were curled up in bed reading Kuroshitsuji for the thousandth time, and the next… you’re standing in the middle of Victorian London, staring at the gates of the Phantomhive Manor.
And then he opens the door.
Sebastian Michaelis.
You almost fall to your knees.
But you don’t. Because that would be suspicious.
Ciel takes you in. Reluctantly.
You’re a girl with no papers, no past, no family name. But you know things you shouldn’t — things no one should. About the Queen’s Watchdog. About the cases he’s solved. About the people who died on the way.
You drop details without realizing it. Names, dates, consequences.
Ciel narrows his eyes.
“You knew what Lau would say before he said it.”
“You knew Soma’s name. He never told you.”
“You told me not to drink the wine at that dinner party… and you were right.”
Eventually, he makes up a reason to explain you away.
A seer, he tells people. Some kind of oracle.
He keeps you under close watch. But lets you stay.
Sebastian, of course, is curious.
But it’s more than that.
You’re terrified of him — and yet you don’t run. You flinch when he touches you, but you never scream. You don’t question the impossible. You accept it.
And when he lets his inhuman nature slip for a split second…
You don’t blink.
That’s when he starts to watch you.
“You’ve been remarkably composed since arriving here,” he says one evening, pouring your tea.
His tone is light, but his eyes are searching.
“Most girls cry. You haven’t cried at all.”
You give him a soft smile and say, “I’ve read about men like you.”
He stills.
Then smiles back.
“Have you, now?”
He tests you. Every chance he gets.
Shows you his true form — just a glimpse. You don’t faint.
Drops a name no one should know. You don’t flinch.
Asks you what you really are. You say nothing.
You won’t give him the satisfaction.
But you start locking your bedroom door at night.
(Not that it would stop him.)
Ciel uses your “visions.”
You feed him leads. Just enough to keep yourself useful. Just enough to stay safe. But it gets harder. Because you know what’s coming. You know how this story ends.
And Sebastian? He’s not bound to your silence.
He watches your eyes whenever someone dies.
Whenever he kills.
And you know he sees it: the guilt. The shame. The familiarity.
He just hasn’t figured out why.
“You’re hiding something precious from me,” he murmurs one evening, shadowing your step in the garden.
“A secret you guard even more fiercely than your soul.”
You laugh, a little too quickly. “Don’t we all?”
He smiles.
But he doesn’t laugh.
You never tell him.
Not when he corners you. Not when he breathes down your neck and calls you little seer, little dove, little liar. Not even when he curls his fingers around your wrist and whispers, “If you know what I am… why do you stay?”
Last month, I'd fallen down the isekai rabbit hole. I've now reached a point where I'm having a hard time keeping track of what I've already seen and what I haven't yet watched. I've also been mixing up one anime for another, or worse I've completely forgotten what happened in it after some time has pass.
I originally wasn't going to put this in any particular order, but decided to list down the ones that I enjoyed watching the most to the least. For me, the least doesn't necessarily mean that it was bad. Just that it was not as memorable, or had a few things about it that bothered me enough to get in the way of my enjoyment of it.
The Saint's Magic Power Is Omnipotent
7th Time Loop [1]
The Weakest Tamer Began a Journey to Pick Up Trash
The Wrong Way to Use Healing Magic
I'm the Villainess, So I'm Taming the Final Boss
The Magical Revolution of the Reincarnated Princess and the Genius Young Lady
Kakuriyo: Bed & Breakfast for Spirits
Chillin' in Another World with Level 2 Super Cheat Powers
Reincarnated as a Sword
Campfire Cooking in Another World with My Absurd Skill
By The Grace of The Gods
In the Land of Leadale
Cautious Hero: The Hero Is Overpowered but Overly Cautious
Handyman Saitou in Another World
My Next Life as a Villainess: All Routes Lead to Doom!
My Unique Skill Makes Me OP Even at Level 1
Ascendance of a Bookworm
The Most Heretical Last Boss Queen
Restaurant to Another World
Fluffy Paradise
Tsukimichi: Moonlit Fantasy
Villainess Level 99: I May Be the Hidden Boss, but I'm Not the Demon Lord
Why Raeliana Ended Up at the Duke's Mansion
I Got a Cheat Skill in Another World and Became Unrivaled in The Real World, Too
The Reincarnation of the Strongest Exorcist in Another World
Trapped in a Dating Sim: The World of Otome Games Is Tough for Mobs
The Great Cleric
How a Realist Hero Rebuilt the Kingdom
I'm in Love with the Villainess
Doctor Elise
Dahlia in Bloom: Crafting a Fresh Start with Magical Tools
That Time I Got Reincarnated as a Slime
Farming Life in Another World
The Faraway Paladin
Reborn as a Vending Machine, Now I Wander the Dungeon
So I'm a Spider, So What?
Parallel World Pharmacy
Grimgar of Fantasy and Ash
My Instant Death Ability Is So Overpowered, No One in This Other World Stands a Chance Against Me
As a Reincarnated Aristocrat, I'll Use My Appraisal Skill to Rise in the World
Skeleton Knight in Another World
The New Gate
Wise Man's Grandchild
The Greatest Demon Lord Is Reborn as a Typical Nobody
Am I Actually the Strongest?
Kemono Michi: Rise Up
No Longer Allowed in Another World
Another World: Raising Kids While Adventuring
My Isekai Life: I Gained a Second Character Class and Became the Strongest Sage in the World
I've Been Killing Slimes for 300 Years and Maxed Out My Level
Didn't I Say to Make My Abilities Average in the Next Life?!
The Aristocrat's Otherworldly Adventure: Serving Gods Who Go Too Far
Log Horizon
Uncle from Another World
Black Summoner
Demon Lord, Retry!
The Dungeon of Black Company
Sweet Reincarnation
The Banished Former Hero Lives as He Pleases
The World's Finest Assassin Gets Reincarnated as an Aristocrat
I Was Reincarnated as the 7th Prince, so I Can Take My Time Perfecting My Magical Ability
Arifureta: From Commonplace to World's Strongest
The Rising of the Shield Hero
Failure Frame: I Became the Strongest and Annihilated Everything With Low-Level Spells
Death March to the Parallel World Rhapsody
The Executioner and Her Way of Life
I Shall Survive Using Potions!
She Professed Herself Pupil of the Wise Man
Notes:
[1] I didn't know at the time, but 7th Time Loop isn't an isekai. It's actually more of a fantasy with time looping in the protagonist's own world, rather of them being a person from the modern world isekai'd to a totally new environment. I stilled enjoyed it, and would have overlooked it if I didn't check out all the Villainess tagged anime.
After Thoughts: I seem to like the slice-of-life, light-hearted, and wholesome types of isekai a lot more than I thought I would. They're so enjoyable, but a part of that is probably because I was more in the mood for them. For example, the last isekai I've watched was Grimgar of Fantasy and Ash. I put it low on my list, not because it was bad, but I just wasn't in the mood for it. I was actually pleasantly surprise that it went through the realistic, grimdark and serious route instead of the usual way.
Other reasons (besides not being in the mood for it) that I may put an anime low on my list is because there were things in it that I didn't like. For example, The Rising of the Shield Hero does an excellent job at provoking the audience reaction of outrage to the shield hero's poor treatment, but I just don't like how it handles a couple of things.
One of those points is slavery, which I didn't realize was such a common occurrence in isekai. The protagonist comes from the 21-century Earth, so they know slavery is wrong. Despite this, they never do anything about it, or even try to fight against it, or worse they actually contribute to it. Of course, they're not under any moral obligation to do something, but it's disappointing when it's set up as an afterthought or used as a gimmick to support the protagonist.
I get it. It would be difficult to stop slavery because it's a systemic issue that would require the dismantling of laws and regulations by those in power. But it makes me wonder why do so many isekai authors even include it at all? If slavery can't be treated with the gravity it deserves given its historical role in destroying millions of human lives, then don't add it into the story. More so, if it has no bearing on the actual main plot, or when it doesn't make much sense to see in lighthearted and wholesome-centric isekai animes.
I also don't care for loli-like or shota-like protagonists. It's adorable when the anime is actually sweet and pure, but not when they're sexualized, or put into fanservice situations. What comes to mind is Lloyd from I Was Reincarnated as the 7th Prince, so I Can Take My Time Perfecting My Magical Ability. It’s not a typical isekai since the protagonist is reborn into the same world—though I could be misremembering that. Either way, his character design in the anime weirds me out, and it only gets worse when Ren shows up.
Another example is I Shall Survive Using Potions. It has an interesting premise, but I dislike the protagonist. It's just so off-putting when all the character designs look the same because of the chibi-style. Plus, knowing that a 22-year-old office lady was 'reborn' into a child body, and plans to find herself a husband in that form (or that she isn't phrase by teen boys or men asking to marry her/pretend to be their fiancé) is disturbing. The entire time watching, I was also wondering when will she use her potion power to age herself up to be physically older. Seriously, the thought cross her mind to disguise herself by changing her hair and eye color, but not her body's age?? She even pointed out that it was such an annoying hindrance for when she wanted to start her own business. Oh, and it's not like it's impossible either because she unintentionally de-aged one of her companions too.
I also don't mind harem elements because some do it well by developing their characters and making their story be more than just pandering. Even if it's not a harem, a lot of the anime I've seen has a lot of female supporting characters surrounding the male protagonists. It's not always a bad thing, but most of the time it's not done very well. They tend to feel more like ornaments to complete a chartacter-type checklist (or just to fawn over the protagonist) than genuine companions.
Other times, the anime was confusing, too boring or took me a while to finally get into it. For example, So I'm a Spider, So What? It took me a bit to get into because I wasn't interested in the going on of her classmates. Every time they appeared I was like, no, go back to spider girl because I wanted to follow her journey the entire way, not these people who I have no interest or real attachment to.
Hmm, I'm not going to remember all the reasons I listed an anime low on my list, the few I do is because they were the ones I recently watched. Of course, over time this list may change because some anime have only one season so far, and could have something in it later on that could make me like it less or like it a bit more.
I know I won't be able to keep up with every new isekai release, so I don’t plan on making another huge list like this again—at least not anytime soon.
