AurEtra

AurEtra is the het ship between Auruo Bossard and Petra Ral from the Attack on Titan fandom.

Canon
Auruo and Petra both graduated from the same division, and on their first mission, they had apparently pissed their pants out of fear. The two were later assigned to both be in the Special Operations Squad, both being one of the Scouts with the most Titan kills. Auruo had seemed to develop some sort of attraction towards her, even saying that it's too early for her to act like her wife. Petra, on the other hand is somewhat harsh to him, such as wishing he bit his tongue and die. She noticed how Auruo tried to imitate Levi's behaviour, and thinks that he's nothing like him.

After Petra was killed by the Female Titan, Auruo expressed great distress and attempted to avenge her, although he ended up dying.

They're often seen in official art together.

Fanon
Despite the lack of screentime this ship had, it's rather popular within the fandom, having over 300 AO3 tags with them. While it is the most written ship for Auruo, another popular ship for Petra, Rivetra, has more fanfictions.

Trivia

 * Isayama described them as an old married couple.