Ephemer and the Kingdom Hearts Union Cross protagonist are going their separate ways for now. The new world Brain’s portal led them to was Wreck-it-Ralph’s Game Central Station, and here they made some interesting discoveries that Ephemer wants to report back to his fellow Union leaders. The protagonist’s Chirithy believes Ralph might be connected to the Data World’s glitches, so Ephemer wants the duo to continue investigating him. Meanwhile, he will go back and relay their theory that the Darklings led the Game Central Station’s Heartless to Data Daybreak Town.
Kingdom Hearts Union Cross quests 910 through 911 reveal which of the new Union leaders received a copy of the Book of Prophecies, as the Master of Masters instructed Ava to give one to a specific member back when he informed her of her role. These quests also act as the second set to clear a Union leader of Strelitzia’s murder. This writing acts as a recap and interpretation of these events, so spoilers ahead.
The only explanation Brain can think of for what’s happening to them all is that they really are in the Data World instead of the real one. Lauriam and Skuld arrived at the control room soon after Ephemer, and all three of their accounts support Brain’s theory: Ven and Skuld witnessed a glitch of Ava and the Master, while Lauriam witnessed one of Strelitzia. Then, according to Ephemer, Game Central Station is inherently a digital world, meaning so were the Heartless that the Darkling’s brought over.
The situation makes the group question whether the real world still exists, but Brain is confident that they were all in it before the glitches started breaking out. If that’s the case, then something — or someone — moved the group from the real world to the digital one, effectively trapping them since their Lanes Between portals won’t take them back to the real world like they normally would.
They don’t have any leads on the culprit, but the Data World’s existence was a closely kept secret. The list of those who knew about it is small, and since they don’t have anything to go off of, Brain thinks they should suspect everyone on it, including Master Ava, whom Ephemer just can’t see doing such a thing giving her effort to keep them safe.
Either way, Brain still plans on becoming a virus, only now he’s going to reconnect the Data World to the real one. He doesn’t know how he’s going to pull it off just yet, but he departs from the group to figure it out. It’s while making his way back to the Foreteller’s Chambers that he reveals himself to be the holder of the copy of the Book of Prophecies, pulling it out of his jacket in wonder if it knows anything about the Dandelions‘ current situation.
Brain received his copy of the Book of Prophecies four years ago on the outskirts of Daybreak Town. Master Ava gave it to him to convince him to become one of the new Union leaders that would take over after the Keyblade War. Before he received the Book, Brain was initially going to refuse the job. In fact, the only reason he accepted it in the first place was because Ava gave him the Book, or more accurately, because of the reason she gave it.
In all honesty, even after learning that the Master of Masters hand-picked him to become a leader, Brain didn’t want to because he was lazy, and it sounded like a lot of work at the time. Also, he deduced that Ava couldn’t tell him who his fellow leaders were because she didn’t want them doing something unexpected to stop the Keyblade War. In his eyes, she wanted a pawn, and he wasn’t anything of the sort.
However, Brain turned out to be wrong about Ava. He assumed that her intentions were the same as the Master of Masters‘, but they weren’t. She managed to convince him of that and of becoming a Union leader by sharing the same view as him on the concept of destiny, a topic she pivoted the conversation to after his refusal. Brain doesn’t like the idea that everything is predetermined for him, and while Ava never says it out loud, her follow-up action of giving him the Book screamed that she felt the same.
The Book of Prophecies, by its very nature, embodies the idea of destiny since it describes how the future will play out, but Ava reasoned that if they all know the future through the Book, then they should know how to change it. Will the Book adapt and change with their actions: who knows, but Ava wanted to try because, like Brain, she didn’t like the idea of being idle when she knew something terrible was going to happen. It’s a trait of hers that was touched on during the “Search For Ephemer” questline.
So, for the sake of changing the future, she gave Brain a copy of the Book of Prophecies. The Master gave her a list that named all the new Union leaders he wanted to be recruited, and to whom among those leaders, he wanted to receive a copy of the Book. Under no circumstances were any of the other leaders to read it. She placed this list between the pages of the Book that detailed the fates of Brain and his team and hoped that Brain would understand why she was doing this when the time came.
However, Brain immediately understood what Ava was up to. She had not only just handed him a list of every other Union leader, but he knew she also deviated from the Master’s orders by giving him the Book — an act that likely led to Luxu calling her the traitor during “the Traitor and the Lost Page” questline. Knowing that Ava was going out on a limb, Brain reassured her that he wouldn’t open the Book unless he absolutely had to, and she assured him that he would know when the right time to do so was.
Kingdom Hearts Union Cross is on Andriod and IOS.