Sein/Synopsis

History
Sein lives in a small village with his older brother. As a child, Sein and his childhood friend Gorilla had a dream of going on an adventure and becoming a hero that nobody will forget. However, due to Sein’s concerns and guilt for his brother, Sein felt obligated to stay in the village, thus he declined the offer of Gorilla to journey on. Instead, he opted to wait for Gorilla to return. At the time of meeting Frieren, a decade has passed since Gorilla went on a journey. Sein believes his friend might have been dead, because Gorilla did not come back after 3 years like he promised. Sein has always wondered, if he had taken a Gorilla hand at the time, things would have been different.

Chapter 27
Per his older brother’s request, Sein went to harvest wildflowers in the forest to use for cooking, in preparation for the Harvest Festival. During his journey, he falls into a bottomless quagmire and is discovered by Frieren. In order to ask for help, he recounts a story of his childhood friend and his dream. He asks Frieren to pull him out by taking his hand, which she refuses as his hand was dirty, and instead uses “magic to pull someone out of a bottomless quagmire” to save him. As an expression of gratitude, he invites Frieren, Fern, and Stark to his village, but they decline as they need to replenish their supplies and prefer to reach a major town by the end of the day.

Sein meets the party again as they seek help from his brother’s church to cure Stark from the snake’s poison. He promptly and effortlessly treats Stark, despite the poison being so difficult that even his brother, who was deemed as the most superior priest of a region by the Holy City, struggled to figure it out. Sein’s brother asks Frieren to take Sein away from the village, as he believed Sein had been searching for someone to support him. Both Stark and Fern were in favor of the proposal, for it would be beneficial to have a priest in the party, and Stark sets out to recruit Sein. Stark finds him gambling at a tavern, and Stark joins the game in the hopes of beating Sein so that he would join the party.

Frieren and Fern come looking for Stark as he is late and find both Stark and Sein stripped bare down to their boxers outside the tavern. Sein asks the party to not judge him, as all adults are dirty. He tells Frieren to find someone else, as he thinks he is a ruined middle-aged man and that it’s too late for him to pursue an adventure. His remarks remind Frieren of how she used to be prior to meeting Himmel, so she spoke to Sein using the same words that Himmel told her before “I’m talking about the story you will have now”. However, Sein doesn’t budge, and Frieren concludes that she despises him, and that is why she chose to invite him to be a comrade regardless, a logic Sein fails to understand.

Chapter 28
Frieren’s party decides to stay in Sein’s village, and attempts to recruit Sein nearly every day. They decide to consult Sein’s older brother about what Sein likes, which was “Alcohol, cigarettes, gambling, and older ladies”. In fact, he aspired to become an adventurer when he was a kid just for the sake of traveling with an older lady. At first, Sein discloses that since his childhood friend Gorilla said he would return in three years but ten years have passed since then, he believes that Gorilla is already dead. However, after being confronted by Frieren, Sein eventually admits that he cannot leave because he cannot abandon his older brother and leave the village, as he also stayed in the village for Sein’s sake when he was a child. Sein’s older brother slaps him, and says “I have not once regretted the decision I made, what about you?”. Sein apologizes to his older brother, and decides to join the Frieren’s party after all, but only to find Gorilla.

Chapter 29
During their stop at the Rat Region, Sein acts as a mediator for Fern and Stark’s quarrel. He tells Fern that she should go after Stark. Sein’s experience in dealing with women is exhibited when he picks out a pouch with a butterfly pattern as a birthday present for Fern. He correctly guesses that Fern and Stark chose a present together for his birthday, and understood Fern’s view of giving presents. Sein tells Fern to hurry and apologize to Stark and to pick out a present together, which she is able to do.

Frieren and Sein meet on a rooftop while spying on the children. Sein says ”Once you're an adult and notice the distance you have with other people, you try to avoid getting into conflicts with them. So that is something exclusively for the young.” Their conversation made Sein realize the maturity level of Frieren’s emotions.

Frieren remembers a conversation she once had with Heiter, where he says “I simply kept acting like an adult in an effort to be one. I am sure I will continue to act like one until I perish”, and Frieren pat Heiter head to give him praise while he was still living in his earth, for Heiter he is still a child at heart and needed lots of praise and support from an adult. Frieren does the same for Sein to praise him and tells him that she believes that he is managing to be a proper adult.

Chapter 30
Sein heals the horse which was slightly injured when the wagon fell. He asks about Fern’s present from Stark, who tells him how he took three hours to pick it. Sein praises Stark for picking that bracelet, saying how he thought Stark was more of a loser. He appears to be familiar with floriography, as he is able to recognize the mirrored lotus flower design on Fern’s bracelet, telling them it means eternal love - “something you give to your beloved”. He seems to have made a conclusion that Fern and Stark have something going on, as he smirks at Fern after she implies the bracelet is important to her.

Chapter 31
As the party approaches Laub Hill, Sein quickly detects that the people of the town were put under the curse. With his natural Goddess’s magic talent, he is able to figure out the specification of the curse, the ritual, and equipment to cancel it,  and also the source of the curse and its location. Following his lead, the party heads to the forest to eradicate the monster, but slowly everyone falls under the curse, with only Sein left able to resist the curse’s hypnotic effect. Sein eventually encounters the floral monster. During the battle,  he is able to recognize the monster type and its weakness. However, his battle magic is not strong enough to fight the monster alone. Despite thinking that he and Frieren haven't had enough time to build a mutual connection and understand each other’s thoughts, Sein decides to listen to Heiter’s story and chooses to believe in Frieren’s words: “Don’t fight it alone. I will definitely defeat it”, so he wakes her up. Within seconds of Frieren waking up, she immediately kills the monster. Afterwards, the village head thanks Sein. As the party leaves the villages, Frieren also thanks Sein and praises him by patting his head, which he returns with a defeated but contented smile.

Chapter 34
The party continues on their journey to the North. As they come across people, Sein would ask about Gorilla and look for eyewitnesses of the warrior’s journey. One of the villagers in town recognizes the name and points them to a stubborn granny who was close with Gorilla. In order to get the granny to talk, the party has to accomplish many of her requests to open up her heart. The last task is to polish the stone status of Great Heroes who saved the world from a long, long time ago. The statues are of a priest and a warrior, who somehow bear a resemblance to Sein and Gorilla.

It is revealed that Sein and Gorilla had seen these Forgotten Hero statues before, and their forgotten story inspired Gorilla to become an unforgettable hero, and named himself Warrior Gorilla, while Sein was named Priest Goatee by Heiter. Once they finish polishing the statues, the old granny is finally pleased and opens up her heart to talk about Warrior Gorilla - that she also asked him to clean the statues, but he couldn’t do it this well, yet his name was clearly impactful, and Gorilla often spoke about Sein. Sein spends time reminiscing with Granny, and finds out that Gorilla went to Tür, a commercial town in the middle of the northern continent, which is in the opposite direction of Äußerst. Sein realizes that he will have to split paths with Frieren’s Party and that his journey with them might come to an end soon.

Chapter 35
Due to an approaching winter storm, Frieren’s party has no choice but to wait in a nearby village, thus Sein is able to stick with the party for a little longer. Again, he has to play mediator for another one of Stark’s and Fern’s quarrels. Sein tells Stark that, unlike Sein, he is a good kid at heart, so he needs to express his true feelings. He also tells Fern that she should reconcile with him if she doesn’t hate him.

Frieren praises Sein for working very hard. Sein remarks that it was only Frieren that would praise him as if he was still a kid. Frieren says “but you are one, aren’t you” and Sein replies “Well, that’s not unpleasant to hear”. Sein asks Frieren why she was so concerned with him, and Frieren responds that he reminded her of herself before meeting Himmel, and it angers her. And that's why she feels the need to give Sein a chance because that’s what Hero Himmel would have done. Himmel and the others gave her the courage to go travelling, and taught her how fun it is to spend time with comrades, and Frieren asks Sein if he thinks it was fun, to which Sein, reminiscing about their journey together, replies “Yeah, it was really fun”.

After the winter has passed, Sein decides to part with the party to pursue Gorilla, because he doesn’t want to bear any regrets anymore. Sein bids farewell to the party, and as he goes on, he laments to himself on how quiet it is when one is alone.