“Sebastian is a rebellious loner who lives in his parents’ basement. He is Maru’s older half-brother, and feels like his sister gets all the attention and adoration, while he is left to rot in the dark. He tends to get deeply absorbed in computer games, comic books, and sci-fi novels, and will sometimes spend great lengths of time pursuing these hobbies alone in his room. He can be a bit unfriendly to people he doesn’t know. Could a charming new farmer cultivate the wasteland of his heart? Who knows?”
Sebastian lives with his mother, Robin, along with his step-dad Demetrius and half-sister Maru. Robin sometimes calls him Sebby. He feels that Maru is treated better than he is, and during Winter will talk about building a snow-goon that Demetrius demands he removes; he will then angrily question what his step-father's problem is.
Sebastian is good friends with Sam; the two can be found hanging out at Sam's house or at the Saloon playing pool. They also stand together at festivals, along with Abigail. It is hinted he may have a crush on Abigail, after Sam tells the player Sebastian really wanted Abigail to be their drummer "for some reason".
During the Flower Dance, if not dancing with the player, Sebastian dances with Abigail.
It is very helpful to try and get him to two or more hearts as soon as you can because otherwise he would be inaccessible as he does spend a lot of time closed in his room.
You find Sebastian working on his computer. When he finishes, he mentions that he's a programmer and is working on a project for a client. There's a notification on his computer, and Sebastian explains that it's Sam asking to hang out, but he would rather not go out. Robin enters his room moments later, telling him that Abigail was looking for him and will stop by later. Sebastian asks whether Robin told her that he was working, and Robin says yes, but Abigail decided that she would probably stop by anyway. Robin leaves the room, and Sebastian expresses his irritation that nobody takes his job seriously.
You see Sebastian working on a motorcycle in the garage at his house. He explains that it belongs to him and sometimes he goes for long rides alone far away from Stardew Valley. He suggests the possibility of you one day taking a ride with him, to which you agree or disagree.
Six Hearts
Enter Sebastian's room when he's there.
Details
Sebastian greets you, and invites you to play Solorian Chronicles: The Game with him. You play through a scenario, for which you'll be given a score between A and D. You're given a choice of archetype (which affects your score but has no effect on friendship):
"Warrior. I like a direct approach."(No effect on friendship.)
"Healer. I prefer to help others."(No effect on friendship.)
"Wizard. A sharp mind is the most powerful blade of all."(No effect on friendship.)
To achieve a score of A: choose healer, go through the front door, attack then shield from the skeleton, go through the green glowy room, enter the hallway to your left, destroy the capsules and heal Sebastian's wizard. Sebastian is grateful, and he single-handedly defeats the boss.
Eight Hearts
Go to the beach on a rainy day between noon and 11pm.
Details
Sebastian is standing on the boardwalk. He's surprised to see you outside in the rain. He says he's anxious around other people, but he doesn't feel that way when he's with you. He takes out an umbrella and motions you to stand under it with him.
Sebastian is outside his house. He says he was about to go for a ride on his motorcycle. You join him for a ride, and he brings you to a place he often goes by himself to think about his life while enjoying a view of the city.
If your character is female, he mentions that he doesn't normally bring girls to this place. Otherwise, he admits that he's never felt this way about other guys, but that you're different.
He pulls on his cigarette a few times, and then asks what you think of the city. You have three options, one of which is telling him to quit smoking. Choosing this one causes Sebastian to be briefly annoyed; he says you sound like his mom, then admits that it's a bad habit and he'll try to stop.
He confesses his true feelings for you, and you embrace under the full moon.
Marriage
Sebastian's room.
Give Sebastian a Mermaid's Pendant to begin your Engagement & Marriage.
Details
After giving Sebastian a Mermaid's Pendant, he is very shocked upon your proposal. He tells you he will set everything up and the ceremony will be in 3 Days. He wears a purple suit, matching his hair color.
Sebastian's addition room on the farmhouse has a similar design to his room at his parents' house - there's a small table, couch and computer. He'll also set up a small area behind the farmhouse for his motorcycle, and sometimes go there to work on it.
Behavior
Sebastian exhibits 2 notable behaviors once married.
“What are you doing in here? I could've been naked!”
After receiving the bouquet
“
“...You want to get more serious? I feel the same way.”
When engaged
“
“When you showed up in town, I never thought I'd be marrying you some day.”
When he visits Robin, after marriage
“
“Mom's face lit up when I walked in. She deserves to be happy.”
When in love / Living on the farm
“
“I often felt unappreciated at home...but here I feel like I really belong. Thanks for making me feel welcome, <spouse name>.”
“
“<spouse name>? I just want to say that I appreciate all the hard work you do for our household.”
“
“Hey. Look at me. Never forget that I love you... you're everything to me.”
“
“Living here with you is teaching me to come out of my shell a little bit. I think it's good for me.”
“
“I may be a reclusive guy, but I'm always happy when you're around.”
“
“Hi <spouse name>! Good to see you. It's comforting when you're around.”
“
“Sometimes I feel so angry...but when you show up I always start to calm down.”
“
“You look cold...here, come closer.”
“
“How was your day? Did you slay any monsters? It feels good to take out your aggression now and then, doesn't it.”
“
“I'll just watch you from here. I enjoy watching you.”
“
“Hey. How'd you sleep last night? I heard you mumbling.You seemed scared, but I have to admit...that was kind of cute.”
“
“I'm trying my best to quit smoking now that we're married...I don't wanna die on you. It's a bad habit. I want to have a future together.”
“
“Hey...want some coffee? I needed some...woke up early from a nightmare and I just couldn't fall back asleep.”
“
“I got up early and watered some crops for you. I hope it makes your job a little easier today.”
“
“I did some work on the laptop today. I was actually brainstorming some ideas for a game I want to make. With your farming income, I can afford to do what I want with my life. It's pretty amazing. Thank you.”
“
“It's really cool to have our own place. I can do whatever I feel like and not have people nagging at me all the time.”
“
“The view from our house is perfect. You can see the sun setting over Pelican Town from the front porch.”
“
“Hey. I was just thinking about my old room in the basement. I felt comfortable there, but this is a lot more interesting. And I don't miss the smell...”
“
“Hm...Sometimes I have to force myself to stay outside for health. I dunno what it is, but I like being indoors. Maybe I'm just so used to my dark basement.”
“
“I'm still trying to adjust to the farm schedule. I used to stay up until 5 am and sleep in until 2pm, sometimes.”
“
“Hey. I couldn't sleep last night so I took a walk to the caves. I found this [item from the mines]...want it?I just have trouble sleeping sometimes, it has nothing to do with you. I love you.”
“
“I need to stay independent, even though we're married. That's just how I am. I still love you, though.”
“
“I'll never grow tired of the rain...especially out here on the countryside.”
“
“Maybe a witch will visit us tonight? Hah...if only life was that interesting...”
“
“I spotted a bat out the window earlier. It's kind of hard to see, but if you stay focused you can often catch them flittering about. They're out there.”
“
“We should raise more slimes. In big quantities they can be really profitable. And the're so easy to raise. Also, different color slimes produce different items. I dunno, I think it'd be kind of a fun hobby for us.”
“
“Sorry if I smell...I was sweating all night in the heat.”
“
“The Stardew Valley Fair is a little crowded for my tastes... but I'll just hang out with Sam. It'll be good to catch up with him. You should play some carnival games,though! Don't worry about me.”
After marriage during the Flower Dance, when asked to be your dance partner
“
“Ugh...Yes dear? Ugh...do we have to? Alright.”
After marriage, before and during the Luau
“
“Have you thought about what you're going to put in the luau soup? I have no idea what's good...you're the chef.”
“
“I'm doing my best to stay in a good mood...”
After marriage, before the Dance of the Moonlight Jellies
“
“The weather's starting to cool of. It feels great. Should we go to the festival tomorrow night? It's actually a tradition I kind of enjoy.”
When jealous
“
“I heard you secretly gave [name] a gift today. Do I have to be suspicious of you?”
When Sebastian gives you a Stardrop
“
“Honey...I wanted to give you that fruit as a symbol of my love.”
During pregnancy
“
“Hun/Sweetheart, can't you tell? You're pregnant.”
After having children
“
“Everything went well, and now little <child's name> is part of the family. We're very fortunate.”
“
“Have you smelled <child's name>? Maybe it's time for a bath...”
“
“Maybe when <child's name> is a little older, I'll get a sidecar for the bike and we can all go for a ride.”
Portraits
Timeline
Sebastian's look evolved over the years the game was in development.
Here's a timeline showing how ConcernedApe's art and Sebastian's style changed over the years before the game was launched.