Rivetra

Rivetra is the het ship between Levi Ackerman and Petra Ral from the Attack on Titan]] fandom.

Canon
There is the scene in episode 21 during the Female Titan Arc when Levi stops to see Petra's dead body. Even though he says nothing, you can just see the sadness in his eyes. Second, in episode 22, Levi takes Petra's badge from her jacket. If you listen closely you can hear the piano version of Call Your Name in the background. Also in episode 22, there is the scene when Petra's body is thrown off of the cart. If you are a manga reader, you know that the scene was never drawn into the manga, signaling that Hajime Isayama sat down and told the directors to add it in. Then there is the infamous "letter scene" with Levi and Petra's father. Also in episode 22.

Next up is all of the quotes the VAs and the Author Hajime Isayama have left for us. During an interview, Levi Ackerman's Japanese voice actor, Kamiya Hiroshi says "リヴァイ的にはペトラ気になりますよね (REGARDING LEVI IT’S PETRA THAT I AM CONCERNED ABOUT.)". The voice actor absolutely adores Petra. Another quote is from Petra Ral's Japanese VA, Natsuki Aikawa. She says in a tweet “Someone told me it would be exciting (moe) if Heichou pushes Petra against the wall (kabedon). I understand! Totally understand!” (This is a rough translation). I believe that this quote pertains to when Petra tells Eren not to be scared of him, and Levi and Petra are left alone in the same room. Lastly for quotes, is what Author, Hajime Isayama, says in a Q&A.

質問「リヴァイからみてペトラは部下として可愛いとか少しはあったのか

先生「そういうところはコマとコマの行間に描かれてると思います」

Q: Does Levi think of Petra as a cute subordinate even a little?

Isayama: I think I have portrayed such thing in between the panels.

Hajime Isayama even admits that there was a connection between the two.

Now for a little section on the English VAs. During the SacAnime Winter 2015 - Attack On Titan Panel, the English voice actors for Annie Leonhart, Mikasa Ackerman, Petra Ral, Levi Ackerman, and Armin Arlert were asked who they shipped in the show. Nobody knew how to answer the question until Lauren Landa (Annie Leonhart) said, "I honestly can probably see - well not anymore, but Petra and Levi.". Matthew Mercer (Levi Ackerman) says "Yeah, I could see that too." which is responded by Caitlin Glass (Petra Ral) with "They would be like the cleaning King and Queen.". Also, during the Attack on Titan panel Q&A at KrakenCon 2014, Matthew Mercer and Caitlin Glass were asked to improv a scene where Petra confesses her feelings to Levi.

Now for the birthday cards and Valentine's Day Events. On Petra's birthday card, it was confirmed that she was the one who picks out Levi's clothes. In the Valentine's Day events, in 2014, they were chosen to be the couple for the event. Don't forget that for the past few years they have been one another's valentines.

Little things:

•Petra is the only one who calls Levi by his first name in Squad Levi.

•Spoof on Titan confirmed Petra's feelings for Levi!

•The line "I'm crying, missing my lover" from the piano version of the song "Call Your Name" is played as Levi gets on one knee to get Petra's badge

•Levi thinks Petra is cute

•They have tea together late at night

Links:

Hajime Isayama quote- https://heartberry.tumblr.com/post/172430363543/terrifying-renegay-pearl-for-the-people-asking

Natsuki Aikawa quote- https://heartberry.tumblr.com/post/172430583163/aikawa-natsuki-petra-rals-va-on-twitter-rough

Hiroshi Kamiya quote- https://heartberry.tumblr.com/post/172430260413/%E3%83%AA%E3%83%B4%E3%82%A1%E3%82%A4%E7%9A%84%E3%81%AB%E3%81%AF%E3%83%9A%E3%83%88%E3%83%A9%E6%B0%97%E3%81%AB%E3%81%AA%E3%82%8A%E3%81%BE%E3%81%99%E3%82%88%E3%81%AD-regarding-levi-its-petra

SacAnime Winter 2015 - Attack On Titan Panel- https://www.youtube.com/watch?v=GZBdZYUoGjg

Attack on Titan panel Q&A at KrakenCon 2014- https://www.youtube.com/watch?v=fXyp6cE9cg8

A little picture of the Rivetra English VAs with a piece of fanart- https://heartberry.tumblr.com/post/172430644833/their-vas-istg