User blog comment:Kaido King of the Beasts/Chapter 831: Oda's Adventure on Acid/@comment-137.175.139.190-20160706020810

I think at the end of the arc, Luffy will tell the retrieval team to head to Wano without him since he will buy time for them to escape while he fought Big Mom. During the battle, it got so intensed that the island collapsed and sanked into the ocean. Either Luffy will defeat Big Mom, getting defeated himself, or both sides will end in a draw where both of them are laying unconcious. Luffy falls into the ocean where he is unexpectedly rescued by an unknown person. A few days later, Luffy wakes up to find himself in a medical room and assumes that his crew went against orders and came to rescue him. However, the truth is that he is on a different ship. When he hears someone coming in, he sees that it's Koala and Hack. Koala cries tears of joy and hugs Luffy while he's confused as to who they are. Luffy asks them what's going on. Hack explains that after his battle with Big Mom, they found him sinking into the ocean. He reveals that they were following the Vivre Card to look for Luffy because they needed his help. Hack mentions that both him and Koala are members of the Revolutionary Army. Luffy realizes that they know Sabo and work for his dad. They confirm it to be true and they revealed that Sabo asked them to find Luffy so they could help them with stopping a big event, which will be revealed in the next arc.