Bertolt Hoover is the Colossal Titan
And Reiner Braun is the Armored Titan
Ho. Ly. Cow.
It's especially shocking because up to this point in the series, Reiner always acted like a big brother to everyone around him.
And it turns out he played a major role telling Annie to head towards Eren's group in the last arc. The clever dude managed to create a message on Annie's hand using his blades when it seemed like she was about to crush him, and he does so after he asks Armin where Eren currently was.
There was also foreshadowing to Reiner's warrior persona about two episodes ago, when Bertolt told Connie, Historia, and Ymir that Reiner "was more of a warrior" back in the past, which triggered a reaction from Reiner that sounded like, "Why did you tell them that, Bertolt?"
The reveal was handled really well. I really like how Reiner and Bertolt initially bring it up very casually to Eren as we see some of the Survey Corps soldiers walk away from them. At that moment, you think Reiner and Bertolt could just be messing around because of how casual they are about, but after the flashback with Armin's explanation, it becomes clear they are not joking around, and the result we get is this amazing scene. It's worth the watch:
*Language warning and blood warning for above video (don't worry, there's no major gore though, and only one swear word is used)*
Everything about this scene was intense. Eren's shocked expression is what you'd expect for a jaw-dropping reveal like this one. Mikasa slashing Reiner and Bertolt in an attempt to kill them, but it ultimately triggers their transformation. The music that plays from then on is a far more intense version of Vogel im Kagif, and I got chills listening to that in combination what was going on.
OK, confession time: I already read the chapter this episode covered long before season 2 started, so I knew the twist was coming, but seeing it all animated with the epic music playing in the background filled me with the same excitement just like when I first read this twist in the manga, and I gotta say, this scene adapted the material from the manga perfectly.
One thing I really liked the anime does here compared to the manga is that in the scene right before Eren transforms, we have a montage of various moments of Eren bonding with Reiner and Braun. In the manga, the only scene from the montage shown was the one when Eren and Armin were sitting at the beds talking with the traitor duo. Here, we get two more clips: when Reiner was training with Eren, and when Bertolt was showing Eren and Armin a book. Adding more scenes of the our heroes bonding with the traitor duo as Titan!Reiner grabs Eren hammers the twist really well. It's like the show is telling you, "And you grew up remembering these guys as the best bros for Eren, but guess what... they... are... TRAITORS!"
I completely sympathize with Eren when he was crying as Titan!Reiner was trying to escape with him. How would you feel if a deeply trusted friend who you always depend on was revealed to be the one responsible for the destruction of your hometown and the death of your mother? You would devastated and enraged that's for sure, and that was exactly what was going on through Eren's mind.
And Yuki Kaji demonstrates what an incredible voice actor he is yet again. He captured Eren's emotions perfectly as he transformed.
"Bertolt... Reiner... YOU DAMN TRAITORS!"
Seriously, his line is chilling to listen to.
In all, this is definitely the best episode of AoT season 2 thus far, and next week's episode will be even better. Eren is going to duke it out against Reiner, while the Survey Corps soldiers on the wall have to deal with Bertolt.
Now, I'm going to go watch the anime-only watchers' reactions to the reveal, because I can already tell their they were utterly shocked.
