Interactions between Annie and her coconspirators—a trio oft-perceived as a unit to complement and contrast the relationship between Armin, Eren, and Mikasa—are curiously sparse. The notion that Reiner and Bertholdt are Annie’s accomplices catches our protagonists off guard precisely because they have not seen them interact with Annie very much at all.
This can be explained with a few arguments: Annie’s preference to work alone, perhaps influenced by her father’s request that she treat the whole world as her enemy; having Annie remain independent cover as a strategic decision to avoid drawing suspicion should she or Bertholdt and Reiner be discovered—which is supported by the lack of concern Reiner or Bertholdt (who were intentionally kept in the dark about Annie’s fate by their superiors) exhibited about leaving Annie behind in enemy territory after blowing their own covers. From a storyteller’s perspective, keeping enough distance between Annie and her accomplices was necessary given the revelation that she is an antagonist came approximately twelve chapters before Bertholdt and Reiner’s. Keeping their interactions few and far between—or at the very least innocuous enough not to raise the reader’s suspicions too soon—was as prudent for Isayama to conserve dramatic tension and impact as it was for Annie, Bertholdt, and Reiner to avoid arousing the enemy’s suspicion.
Hindsight is 20/20, of course. Now that Reiner and Bertholdt’s complicity in Annie’s actions has been ascertained, it’s particularly eye-opening to reread earlier chapters and marvel at how the signs were right there, gosh. I sure know I did.
Even in light of the recent plot developments, however, Annie’s dealings with her coconspirators remain distant. Moreover, there are rather sinister undertones to their interactions that indicate tension and a certain amount of distrust may be lurking beneath the surface of the warriors’ relationship with Annie.
Should you read on, watch out for speculative examinations of very short exchanges and spoilers through Chapter 48 of the manga!