─ A long and justified thread about why Levi and Erwin relationship seen in a romantic way is VALID and people should consider them more:

#Eruri

Erwin and Levi first met in " A Choice with no regrets ", a official prequel dedicated to their meeting and to how Levi joined the Survey Corps. At the beginning Levi's goal was to kill him, but he ended ackerbonding with him and saying he will follow him until his own death.

What does the Ackerbond mean? The Ackermans choose a person to protect, to bound with and it's a part of their bloodline to choose a person to dedicate their life to.

« For Levi, that person is Erwin, whose existence exceedes that of Levi's own », Isayama's words.

Since the first moment Erwin was amazed by Levi's skills and wanted him to join the SC. He recognized his talent and at the end he showed him that Titans are the real enemies of their world. Levi was shocked, he recognized the truth in Erwin's words and his ackerbond awaked

From the first moment in the Attack on Titan anime we see that Levi trusts Erwin to death and that they share a deep and mutual relationship based on trust and respect.
Even if subordinate, Levi is often salty with Erwin, but he never seems bothered by it.
There is confidence

It was officially found in an interview with an AOT director that Erwin's type is someone who understands him and is willing to support him. This perfectly fits with Levi, who has always been there for Erwin and is someone who that will follow Erwin to Hell if he asked.

On the other side, there is an official interview with Isayama where they asked him what kind of women Levi likes.
As you can read Isayama's answer is very clear, Levi likes tall PEOPLE. He didn't specifically said men or women and Erwin is one of the tallest characters.

They deleted the scene in the anime, but when Erwin's arm was bitten off Levi was very worried for him, even if he remained salty as always

Levi broke this man's arm when he said Erwin would have been the first one executed.

This is the scene were they met during the Rod Reiss Titan scene and they reaction hearing each others name is more highlighted in the manga.

Erwin wanted to join the Wall Maria mission and Levi was SO worried about him and about his safety. He tried everything to convince him to not go and he looked really devastated when he failed. That night he ended up staying alone in a corner

The whole Wall Maria mission is incredibly important to prove how much their relationship is MORE than just friendship. The following quotes are from ISAYAMA himself, this is what the promise scene and the whole Midnight Sun really mean.

« Looking at Erwin, Levi felt that Erwin wanted Levi to say "Give up on your dream and die". He caught what Erwin wants. With Levi's words, Erwin was transformed to an adult who can give up his dream »

« Erwin was a slave to his dream. As long as he is alive, he will never get over his dream and death is the only way to free him. Levi giving up the chance to save Erwin for himself and realised Erwin from being a slave to his dream.
Levi understood Erwin's feelings. »

« Kenny didn't use the injection for himself but gave it to Levi. For Levi this was a totally selfless act he never thought a man like Kenny would ever do. Influenced by this experience, Levi chose to not restore Erwin to life but treat him as a human and let him go. »

« Levi lost Erwin, who is someone irreplaceable to him »

« Levi's like a balloon dangling in the air. To Levi, staying with Erwin until Erwin's last minutes gave him a feeling that he has accomplished everything he needs to. Of course Levi still wants to kill the Beast Titan.»

The famous " Give up on your dream and die " is something Levi understand Erwin needs.
And he PROMISED him to kill the Beast Titan.
Levi always put him first and when there was a chance if using the serum he thought about Erwin first. Only one man.

HE PROMISED and he promised with a little heart on his cheek.
A heart, the one Levi dedicated to Erwin and the most classical symbol of love.

At the beginning Levi wanted desperately to bring his Erwin back, but then he realized the pain, guilt and depression that hunted him.
Levi decided to let Erwin rest, he DID it for HIM.
Not because of Eren or Armin, but because he again put Erwin's happiness first.

Levi's so soft during his last moments with Erwin. The delicate way he put his body on the roof, the soft voice when he says « He's still breathing. He's still alive » and his face when Floch brings Erwin's body.
He's so vulnerable and exposed.
He realized he can have him back

Levi is the only one looking at Erwin's body when the other ones are all focused on Armin turning into a Titan.

The promise Levi made to Erwin is something that is incredibly important to him. He is often thinking about him and the promise he made him is somehow keeping him alive.
Levi is really keeping Erwin alive.

Levi wakes up after being badly injured and his first thought is AGAIN Zeke and the promise he made Erwin to kill him.

The world is ending, Levi is now totally physically and emotional exhausted and he is still thinking about Erwin and the promise he made him.
Erwin in his thoughts seems sad and Levi looks definitely desperate.

He thinks about all this comrades, but Erwin is the first one.

There is the Hell in Earth and Levi says he doesn't regret not choosing Erwin, in my opinion because he doesn't want him to experience the same pain they are. He is glad he made him finally rest, like he is in peace.

This is on of the best statements about Eruri EVER.

« You can say it's friendship, but of course there is emotion between them which cannot be concluded as "friendship" »

There is STILL a lot to say, but I am concluding bringing back two parallels. The first is between Erwin/Levi and Ymir/Historia, the lesbian canon couple in Attack on Titan.

The second is the " Thank you " both Erwin and Mikasa say to Levi and Eren in a very deep way and in a tragic moment.
And Mikasa is canonically in love with Eren.

As you can see, I didn't lie when I said LONG thread. I really hope you enjoyed , thank SO much for checking this out

[ I already can see a lot of private qrt ]

ONE last thing. People are always using Marie to invalidate Eruri. She is Nile's wife and as you can see Erwin HAD a crush on her when they were teenagers.
First, we don't only love one person during our live and Erwin could simply be bisexual. It doesn't prove anything

Levi is THE ONLY ONE who went back to Shiganshina to bring back Erwin's body and he is the one who buried him.

I don't want to go TOO much into merchandise and official arts because we know they are here to be sold, but I think we can bring back the Animedia magazine scan with Eruri in the middle and " Oh, my soulmate " on the right.

This is another important official art.
We can see three eyes.
Eren has the Smiling Titan.
Mikasa has Eren.
Levi has ERWIN.

Maybe what they desire the most? Eren wants to kill Dina, Mikasa and Levi want to stay with Eren and Erwin.

And we know Mikasa canonically loves Eren.

Levi is NOT mad with Erwin for hiding his dream. He is more intrigued by him.

« But he gradually stopped..he wasn't doubting Erwin. He felt Erwin was mysterious. [..] He was interested and reacted with ' Well, it can't be helped, I'll help you with it then. ' »

This is one of the best Eruri official arts and their hands are SO close.
Isayama made it even better saying something about it:

« There was no special intention, but for these two, I think it's normal for their hands to touch.
Their hands just moved on their own »

Erwin and Levi connection is NOT one sided, Isayama specifically said that they share a MUTUAL and EQUAL relationship.

Some Attack on Titan characters have official songs. Levi has one as well and this is the last minute of his after-song monologue.
Another reminder of how much he trusts Erwin.

« Even if Erwin will lead me to Hell, I will never regret it. Never. Not even a bit. »

This is a supplementary thread fully dedicated to the " Midnight Sun " episode, an incredibly dramatic but also important moment for Levi and Erwin relationship. https://twitter.com/rivaisheart/status/1374044840908972035

There is an official art of Levi visiting Erwin's grave.
The chosen flower is edelweiss.
The meaning of this flower is deep love, devotion and also sacrifice.

I personally think that it perfectly describes Levi and Erwin relationship.

This literally happened yesterday.
Kamiya Hiroshi, Levi's voice actor, marked again how much Erwin's death affected Levi.
There is nothing left now that Erwin is gone.