EreHisu

EreHisu is the het ship between Eren Jaeger and Historia Reiss from the Attack on Titan fandom.

Canon
In the "Distress" OVA, Eren refused to abandon Historia (then Krista) when she was taken hostage by thieves, and was even willing to rescue her without the help of the others. He did, however, accept the help of Jean and the two of them ended up rescuing her with team work.

Eren openly stated that he liked Historia as a person, a sentiment which genuinely made her happy. Eren’s admiration and respect for Historia only deepened when she defied her father, at which point she tried to rescue Eren because she could not stand to hear him crying about his worthlessness.

When Eren suggested allowing himself to get eaten by Rod, Historia argued that this was not solve anything and then comforted Eren about his father, explaining that he had to take back the founding titan for the sake of humanity.

Eren later thought to himself about how strong he thought Historia had become when she was talking to Erwin and fighting for her right to settle her own fate. Historia then killed her father and declared herself the true ruler of the Walls.

Two months later, Eren spoke fondly of Historia while he, Jean and Armin watched her scolding some kids on her orphan farm. While the two were walking and talking Eren told her she was amazing.

Eren refrained from telling anyone about Dina for an entire year because he feared Historia would be turned into a titan as a result. Eren later smiled at Historia when she expressed her delight at having Hizuru as an ally and stood up against the idea of Historia sacrificing herself and her children for the future of Eldia.

Fanon
Some fans are currently speculating that Eren is the father of the child Historia is now carrying. However, the possibility of this is only very slight since he was opposed to the idea of sacrificing her in the first place. In addition, Eren is destined to die in four years (due to Ymir's curse) and, thus, would be unable to continuously impregnate Historia for 13 years.

Fandom
AO3