FarIsa

FarIsa is the het ship between Farlan Church and Isabel Magnolia from the Attack on Titan fandom.

Canon
Isabel and Farlan are close and live together. Despite the fact that the two of them are complete opposites, they are very important in each other's lives. In fact, in a flashback in the No Regrets manga, it's revealed that Farlan is very perceptive of Isabel's inner feelings. One day, after she came back home, disheveled and bruised, suspectedly by the hands of some "low life scum bags" Farlan and Levi knew about, when asked what happened, Isabel claims she fell. After being asked further about the issue, she flinches and runs off saying her hair will grow back. Furlan later hears her crying and muttering of killing those who hurt her. And somberly thinks about how the Underground is negatively affecting her and Levi as well.

The two of them seem to be closer in the group as they grow, as Levi starts acting more on his own as they make it out of the Underground. For example, after they joined the Survey Corps, one night Levi went up to the roof to have some time alone to reflect on how to help his friends, Isabel and Farlan. Meanwhile, the two of them were out getting some wine and ended up looking for Levi. Once they find him alone there, they joke about him keeping the night sky view all to himself, and join him.

On their first expedition outside the walls, the two of them masterfully battle together to immobilize a titan. However, and unfortunately, on the next day of the expedition, due to heavy rain, Isabel and Farlan end up separating from Levi, who goes after Erwin. After Levi rides off to find Erwin, five Titans, having just devoured another squad, attack the squad Isabel and Furlan are a part of. Isabel is quick to worry about her comrades, but Farlan shouts for her to focus on getting out of there safely, worried about her safety.

As they attempt to flee, a Titan jumps out of the fog, causing Farlan's horse to fall back onto his leg, pinning him to the ground. Unable to move, he can't defend himself against the Titan. At that moment, Isabel jumps off her horse and saves Farlan's life by slashing the Titan's fingers. But as she tries to assist Farlan in their escape, she swings around it in an attempt to cut its nape but misses. She gives it a second try, but slips face-first onto the Titan's back, knocking her off balance. Hanging by one wire and barely coming to her senses, she sees a second Titan. She is gripped by fear as it smiles at her and prepares to attack. The Titan launches itself straight at her, killing her on the back of the Titan she was still attached to.

Seeing Isabel die enrages Farlan so much that he is able to confront the Titans all by himself. However, being all alone against them, and having badly damaged his equipment, Farlan also gets devoured, as Levi arrives and watches in horror.

Levi frequently remembers his dead comrades, and Farlan and Isabel are always present in his mind each time. The two of them are always side by side in Levi's mind.

Fanon
FarIsa is a rare ship within the Attack on Titan fandom mainly due to the fact that the two of them are part of a side story in the AoT series, focused on how Levi met Erwin and joined the Survey Corps. In fanworks, the two of them are usually portray getting married once they're older, in a future where they get to survive, and often in double dates or portrayed alongside Erwin and Levi.