The OA Season 2: What Does The Ending Really Mean?
4. The OA Has A "Brother" In Every Dimension
Old Night tells Prairie that she has a "brother" in every dimension who was sent to protect her by someone referred to as "she." It’s unclear who Old Night meant by “she,” but it could be Khatun.
In Season 1, Riz Ahmed guest stars as Elias, an FBI Agent who appears again during a time in need in Season 2. He tells BBA and the kids that he’s there to help Prairie in her journey as the OA, because he knows she’s “going to need it.”
Elias also had some knowledge about the multi-verse and helps BBA sense people across dimensions. From this, it seems very obvious that he’s OA’s brother in dimension one and he knows this.
Prairie’s brother in dimension two could be Karim as he helps her in many ways throughout Season 2. He’s also greatly tied to the House and was seen by many people in their dreams, so he definitely has some importance.
As Steve travelled to dimension three at the end, perhaps he’s going to be her brother there. It’s hard to know the requirements for this brother, especially as Elias knew his part whilst the others are less certain of their roles and what exactly is happening.