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.