Episode 13

Gathering herbs alone in the Alt Woods, Frieren falls into talk with a man who once longed to adventure before writing the wish off as childish. He admits he spurned a dear friend's invitation years back and has regretted it since. Mid-confession, he is revealed to be sinking in a bottomless swamp; Frieren hesitates over his mud-slick hand, then recalls the spell that frees him. The party walks him home but moves on, only for a snake's venom to fell Stark, who starts bleeding from the nose. Unable to read the poison as a non-priest, Frieren doubles back to the village chapel. The elder priest there calls the bite hopeless until his younger brother appears, the very man from the swamp, named Sein, who lifts the poison with one casual touch.

That senior priest, bearer of a rare regional honor, is awed by Sein's gift and asks the elf to take him along, certain Sein has been waiting for a push to rekindle his dream. A card game meant to recruit Sein instead strips Stark of everything he owns. Frieren keeps pressing anyway, leaning on Himmel's old wisdom about living in the now, and announces she will make Sein a companion precisely because she dislikes how much he mirrors her younger self. Sein, bound by guilt toward the brother who raised him, refuses again and again. Only when he learns the brother once turned down a posting in the Holy City for his sake, and is slapped and told the choice carried no regret, does Sein relent, apologize, and join the group to chase his lost friend.

Frieren pulls Sein out of a bottomless swamp, then races back to his village after a snake poisons Stark. Sein clears the venom in an instant, displaying a healing gift that outclasses even the region's foremost priest. His brother urges Frieren to take Sein traveling.

A botched recruitment over gambling follows, but Frieren persists with Himmel's creed of fixing one's eyes on the now. The brother slaps Sein and makes clear he never gave up his own dreams, freeing Sein to seek his lost friend and sign on with the party.

The anime stages the snakebite directly, whereas the manga only shows the snake already dangling from Stark's arm and adds Frieren stamping on it. A flashback of a young Sein scaling the church bell tower with his brother is unique to the adaptation, swapping out a plainer walking scene.

The inn and tavern read as a single building on screen but as separate spots in print. An added volume-extra beat has Fern lay her coat over Stark, and the anime lets her recover both men's belongings at no cost rather than rebuying them cheaply. As Sein agrees to come along, Stark lands a fish, a touch that echoes a chapter cover instead of any specific panel.