Tinfoil hat theory time!

[Lothengriol]

He lost it, got himself a better replacement, returned and found his lost mace, but didn't needed it since he already got a replacement, so he sells it to you. It's "lost" not in the sense it was lost permanently, but in the sense it was lost once previously.

Sure, it's "lost" in the sense that it was once lost, that makes sense. But I don't think we have any evidence that Sebastian replaced it. Maybe he's not into having replicas anymore.

ABIGAIL IS NOT A MEMBER. Her whole questline is about getting into the guild and it ends with her being on trial run for it, not an accepted member.
Seb could be a member tho, that I have to admit. Altho it would be kinda weird for literally noone to ever mention it, including himself, seeing it's kinda big deal.
Also I just remembered his reaction to caged monsters on Halloween - "Would be cool to have one of these on the farm" - like, whaaaaaat... Not only is he not scared, he's outright friendly towards these things, that's a tone kids can ask "Can we keep him?" about some stray puppy.

It's still fair to assume that at some point Abigail manages to kill ten slimes, right?

That's not an assumption, he literally tells you this. That he just plopped his tent there and have been living there ever since. Like, sure, it's another world and maybe Ferngil government isn't as draconic to its citizens, but the basic control mechanics have to exist for there to be ANY government, such as registration, medical appointments, etc. The latter is actually another point of Linus being an illegal \ semi-legal settler there, as he never visits Harvey's clinic - sure, he might not believe in power of modern medicine and would probably refuse to take any, but he still has to attend annual checkups, since an ill citizen is as much of a liability to others as they are to themselves, and Linus isn't a selfish guy. He's also quite smart and educated, so he would've known that.

He tells you he lives in a tent yeah, but there are other people who live in Stardew Valley that don't have yearly checkups, either. Kent, Maru, and Leo don't. The Farmer doesn't, either. Also, I have never heard of annual checkups being required by law. I haven't been to the doctor in years, though if I had more than a cold I definitely would go. I think Linus is clever enough to have the legal side of things squared away. Perhaps he maintains a Post Office Box in Zuzu City. We know he sometimes rides below the bus rather than pay a fare (as he does with the Desert Festival).

Oookay, that's a whole other can of worms :\ I disagree hardly, but I don't know how fitting a dispute on nature of good and evil will be here per se, seeing as this is the topic about tinfoilhat theories XD

We don't need to get into how or whether good and evil are represented in Stardew Valley, my main point is that people have good reason to dislike void energy and void items, while Sebastian is attracted to them as he's attracted to dark/creepy/dangerous things.

The universal groups aren't called universal just because it's a nice word, you know :\ Pretty much everyone hates those. If we will count those, then literally every other townie can be described as "extremely picky", because they all have the same 100+ items in their hate list. It's like just because you have 1 guy that likes the smell of smoke doesn't suddenly make smoking a good and healthy habit, you know?

I wasn't citing the Universal Hates as evidence that Sebastian is picky, I was showing all of his dislikes. My point is that Sebastian hates nearly all artisan goods, and is the only adult character to do so. He is also the only character in the game who hates eggs (except void eggs). A few other adults (Clint and George, though George at least likes Daffodils) dislike flowers, but they both like most artisan goods. And Leo, who's still a kid, likes all artisan goods except for alcohol and coffee drinks (though of course all these things are new and exciting to him, so he's a bit outside of the norm). So in addition to those five items explicitly shown on the Stardew Valley Wiki page, Sebastian hates: Aged Roe, Beer, Caviar, Cheese, Cloth, Dried Fruit, Dried Mushrooms, Goat Cheese, Honey, Jelly, Juice, Mayonnaise, Mead, Pale Ale, Raisins, Smoked Fish, Truffle Oil, Wine, Chicken Egg, Duck Egg, Golden Chicken Eggs, and Ostrich Eggs.

Also, interestingly enough, Krobus and Sebastian share only one loved gift, Void Mayonnaise, meaning that Sebastian's loved gift taste is as similar to Krobus' as Evelyn, Gus, Jodi, Marnie, and Clint's loved gift tastes. There are three characters who share two loved gifts with Krobus, Abigail (Pumpkin, Monster Compendium), Penny (Diamond, Monster Compendium), and Maru (Diamond, Iridium Bar). There's even a character who shares THREE loved gifts with Krobus: Willy (Pumpkin, Diamond, Iridium Bar).

Again, not the point I was making, my point was that pumpkin soup is both unremarkable (not to slander Ro's cooking here, I meant the recipe itself isn't some extravagant dish made with 100500 rare ingredients and a gold leaf or whatev) and readily available, there is no reason to be all wishy-washy about it. Also the "brings back memories" reply you get when you gift him soup BEFORE you marry him, and in marriage he will reply that Ro used to make it, so that's why it sounds unusually somber to me - like the soup you make reminds him of the soup Ro used to make, but for some reason doesn't anymore.
Like, picture yourself in this - if I invite you out to dinner and treat you to a turkey, you'd probably say something like "oh, that tastes almost like my granny's!" - as in, like the one your granny makes every family gathering and would probably make it again for the next gathering. Buuuuuut if your granny have already passed, THIS is where the "used to make" construct would turn up, because, you know, it would be past tense and there won't be any future turkeys on gatherings for you.
This is what I mean, that he talks about the soup all in past tense, as something that USED TO be there but ISN'T anymore.
Granted, its probably tied more to his dad disappearing into the sunset than to anything else (Ro doesn't love pumpkin soup, so she most likely learned to make it for Seb's father, whom he inherited the love for it from, and probably stopped making it after whatever happened between them).
But that's the thing with theories. You gather a mountain of things that can all be explained individually, yes - or can all be explained with one common reason, there is non-zero probability that this common reason is indeed the root of it all. Occam's razor and all that.

It does matter that the pumpkin soup is unremarkable, but in the opposite way you're thinking. It's his great-grandmother's (on Robin's side) recipe and he has fond memories of his mother making it for him. Of course he thinks of them when he has some. I love clam chowder and it brings me fond memories of my home, and that's not much more than clams, milk, and potatoes. Or in Stardew Valley, just the first two ingredients. Simpler foods are the foods we have more often, and there is a fair amount of study (and representation in media, as Marcel Proust and more recently, Pixar's Ratatouille have shown us) of the phenomenon of simple foods from childhood recalling someone back to their old childhood memories.

Also, Sebastian only says Robin used to make it for him after he's married and is no longer living in his mother's house. It wouldn't be all that weird for Sebastian to say Robin used to make pumpkin soup for him in the Fall while he still lived in her house, because Sebastian and Maru are both adults and probably are used to making/getting their own food by the time the Farmer moves in to Stardew Valley. Explicit sit-down mealtimes often become less frequent as the children of the household grow up. As you've mentioned Occam's Razor, it stands that these simple, logical explanations I've stated here, that make the fewest assumptions, are most likely to be correct. You don't need to assume anything we don't already know such as Robin not liking a recipe from her grandmother enough to make it for herself, Sebastian's father loving pumpkin soup, Sebastian getting his love of pumpkin soup from his father, and Robin no longer making it after Sebastian's father is no longer around. Really, the fact that the pumpkin soup recipe comes from Robin's grandmother (as Robin writes when she mails you the recipe) should be enough to suggest it's Robin herself who chooses to make it when pumpkins are in season.

As a final note, I only caught this now as I write this message, but Krobus doesn't love pumpkin soup, he dislikes it. Krobus does like pumpkins, however Sebastian (along with most of the Stardew Valley characters) only likes pumpkins.

 

[LRangerR]

What if Demetrius noticed how much Sebastian likes it, and told Robin that he doesn't like it (despite actually liking it), so she stopped making it.

The absolute rudest

 

[Magically Clueless]

It's a fun theory! I had a silly crackpot theory before about Sebastian being half-merman and implying his dad was a full merman due to rain shenanigans and some other reasons I totally forgot about. Maybe Sebastian doesn't have a "real" father at all and he was born via MAGIC. Regardless, Demetrius is the father that's been in his life the most, at least since he was a very small kid (this is evident because Maru is also a marriage candidate, so their age gap isn't that large)

Sebastian never actually mentions his father in a direct sense, he just says that Demetrius isn't his real father. I guess that's technically talking about his father but that's a stretch to me personally

I personally do associate Sebastian as being a goth (and I don't consider Abigail much of a goth but rather someone who has an interest in the occult), you don't have to have a bunch of stuff going on to align yourself with it. It's clearly an aesthetic he likes, he likes dark and broody things and he's a little dark and broody himself which is also why he likes void eggs and drinking tea after dark

That being said tho, if it's a fun idea, it's a fun idea. I like any theories that don't make anyone cheat on anyone else lol

p.s. to politely correct a post above, Sebastian hates void mayonnaise and all mayonnaise. He loves void eggs because of how they look (the implication is there in that he wants to display it, rather than do anything specific to it)

 

[dragonflySky]

I just thought that Robin was married before to somebody in the city and Sebastian doesn't much like Maru or Demetrius. Maru and Demetrius don't talk about him because why would they. The townsfolk don't gossip about it because it's kind of boring. He like void eggs. Well I like void eggs and love it when the witch makes one for me so I don't have to buy one from Krobus. On pumpkins, Abigail and Willy like pumpkins and well pumpkin soup is basically just pumpkin cooked and smashed. But Krobus as Sebastian's father is a weird thought. Robin doing it with Krobus is a weirder thought.

 

[Farmer Evie]

I love this theory of Sebastian being part shadow-being, BUT how would Robin have agreed to making out with Krobus, or any shadow being for that matter?
1. While I don't know the true powers of shadow beings, they could have the power to control & erase minds, or shapeshift. Either would have allowed them to trick Robin into making out with them because: they could have controlled Robin's mind to make out with them, and then wipe her mind after so she would have no memory of it happening, or they shapeshifted to look like a human so that Robin had no suspicions.
2. Robin is aquainted with shadow beings herself OR she is part shadow being, but chose to be more human, and got her shadow being parent to erase her mind so that she thought that she was just a normal human.

 

[Farmer Evie]

Maybe Sebastian doesn't have a "real" father at all and he was born via MAGIC. Regardless, Demetrius is the father that's been in his life the most, at least since he was a very small kid (this is evident because Maru is also a marriage candidate, so their age gap isn't that large)

HOLD UP!! 's parents are and ?? I mean I guess it makes sense because she really is a mix of both, but still, I thought Maru had no relation to Robin and Seb at all!

 

[mare]

Maybe Sebastian is actually a homunculus?!
His father is barely ever mentioned, he is active at night, and he wears a T-shirt in summer without getting a tan…


Maybe he has a magical crest on his body and is a mage who uses minerals for magic. Perhaps he’s even secretly participating in the Holy Grail War!

 

[NestorGB]

No, not about Aby and Wizard, that's been done to death ==

Lets talk everyone's darling basement dweller instead.
Seb is odd. Like, actually odd once you start reading and piecing stuff together. Here's some weirdness I managed to hoard:
1) He's the only townie not in the Guild who is canonically armed and regularly does mine runs on his own accord. And Marlon doesn't have anything to say on the topic, which means either he doesn't know or for some reason he is fine with a (formally) untrained civilian being down there alone, which is... you know
2) You can actually pinpoint exactly WHERE Seb is going in the mines based on the gemstones he can sometimes gift you if you are married to him and his own interest in obsidian and frozen tears. He's going all the way down to lava caverns. Which is an impressive feat for us, the player, wearing enchanted rings, protective boots, and all that. Seb is going there with just his mace in hand, and returns reliably without so much as a scratch. He is either a natural combat genius (which would make his interest in Combat Quarterly book look kinda weird), or there is something else going on... (more on that later)
3) If you gift him a piece of obsidian, his immediate reaction will be to fashion it into a dagger. Which wouldn't be odd for a goth or emo... Except Seb is NEITHER. Abigail is. Seb, despite his preferences in darker colors, never expresses any allegiance to any subculture, as well as any interests typical of such cultures. He does DM a DnD-like campaign for his friends, but that's a geek hobby, not goth \ emo one, and his preferred role is a wizard, not a necromancer or vampire, that would've suited a goth \ emo. So where is this obsidian-crafting interest comes from? Also mind that he specifically mentions a DAGGER. Obsidian is a very interesting mineral. Also commonly known as "volcanic glass", it forms when lava is cooled rapidly, and its two most known features are: being hell-of-a-piece to work on and forming EXTREMELY SHARP edges, which made it a beloved material of civilizations like aztecs to make ritual knives from. Case in point - Seb knows exactly what obsidian is best used for and how to work it, which is, again, NOT a common skill. And again, ties back to volcanic levels of the mines. Also the exact quote has him admitting he was LOOKING for it, as in - deliberately searching for a specific mineral. It's not just him seeing a pretty rock and getting an idea to make something cool with it in the moment, that obsidian dagger project has been in the works for at least for some time prior.
4)“Whoa... This egg speaks to me... I'll put it on my desk. Thanks!" - that's his reaction to a void egg. Which is... I mean, this is straight up "WTF?!" on so many levels. First of all - "SPEAKS"?! That's definitely an interesting choice of words right there. Why not say it is cool, or he digs it, or something like that? But ok, it can be chalked to just a manner of speech. However if you talk to him again directly after, he expresses his plans to try and hatch it. Which, again, is a major "WTF?!!!" moment, because here's the thing - the only other being in the entire game with similar disposition towards those eggs is Krobus, who sells them. A shadowfolk. Literally every other human in the game is very obviously repulsed and weirded out by both the eggs itself, the mayo made from it and even the chickens that it hatches into. Even Abi and Rasmodius are, despite being an actual goth and a genuine wizard. Yet Seb is somehow fascinated with those and is genuenly excited about perspective of hatching one.
5) Seb is the only one to mention his father. Literally nobody else ever mentions the guy or whatever happened to him, which is kinda uncharacteristic of a small somewhat isolated community. I used to live in a rural countryside, village people gossip like magpies, and you even see some of that in other townies cutscenes. But Seb's father is a taboo topic for some reason? Almost like something really bad happened to the guy. Something anyone would rather forget...
6) He hates clay. Not just dislikes, like most townies, but specifically HATES. And while he's not the only one with that specific antipathy, he's the only one for whom its kinda unexplainable - kids naturally hate it because they would be regularly scolded by their parents for dirty clothes, Haley and Abigail also don't like getting dirty (but both also regularly have to), Mulners are also easily explainable - George is wheelchair-bound, clearing clay out of tires is a royal pain, and Evelyn's hobby is gardening, so again, understandable. But why Seb would be annoyed by clay? His engine isn't a dirtbike, it's a HD-like motorcycle built for asphalt, and Seb himself states he sticks to roads on his nightly rides, so that's not because of the cleaning reasons, and he doesn't have a hobby or work that would have him digging in clay, so again - no reason here for him to hate it, right?
7)“Hey, thank you. I'll drink this when the sky gets dark.” - reaction to the Stardrop Tea. Again, nothing interesting in itself... until you remember that he's often out at night, either on a bike or in the mines.
8) Pumpkin Soup is another item he likes that is inconspiquous on its own, but becomes really sus when you remember that its yet another favorite he shares with Krobus. Add to it the quote of this soup "bringing back memories" - like, that's a simple seasonal soup that is readily awailable every fall, yet Seb talks about it like there is something else tied to it that he can no longer experience.
9) There is an interesting commentary you might catch if you're married and you talk to him at ice-fishing festival - he'll say he "never gets cold". And it isn't just him bragging - his winter outfit is a scarf over his biker jacket, and that's all. He will even continue working on his bike in winter, despite the snow. Yet he's also the only one in the entire town who stays dressed on the beach (wearing white t-shirt). If you don't know - temperature tolerance is a slider, if you have high tolerance of the cold - you'll have equaly low tolerance of the heat. He should've caught a heatstroke staying in the sun dressed, yet somehow he's fine not even staying in the shadow. Almost like he doesn't feel the temperature altogether...

Ok, I'm done pulling legs. I believe Seb is half-shadowfolk.
Way too many things align way too well. Same preferences as Krobus, same reaction to the void oddities literally every human character is repulsed by, him galivanting extremely dangerous lower levels of the mine like his own backyard, knowing how to work materials that are native to said levels, not being bothered by temperature difference, odd comments here and there... There is just too many coincidences for it all to be coincidental.

...or I'm just out of my marbles XD Your choice~

I'm jealous now. I also want to have a shadowfolk daddy!

 

[NestorGB]

I'm jealous now. I also want to have a shadowfolk daddy!

HOLD UP!! 's parents are and ?? I mean I guess it makes sense because she really is a mix of both, but still, I thought Maru had no relation to Robin and Seb at all!

I thought that Maru is the kid who Robin and Demetrius got together, and Seb coming from an earlier marriage (or whatever that guy comes from)

 

[Farmer Evie]

I thought that Maru is the kid who Robin and Demetrius got together, and Seb coming from an earlier marriage (or whatever that guy comes from)

so then how old was seb when they had maru because they are both of a similar age

 

[NestorGB]

so then how old was seb when they had maru because they are both of a similar age

Maybe Seb's dad left when he got born? some fathers do that (*sob*)