Okay, so black holes can get big... very big. Should all the mass and energy in our universe be equal to one Planck Volume, let's predict a black hole can reach 25% to 35% 1PV. Our hefty buddy will wander through empty (+/-) space until it joins a friend from some other universe... assuming there is a multi-verse. The two become good friends until they run into yet another stray. Now, I'm going to go ahead and posit a limit to just how massive things can get until some as-yet-to-be quantity of stuff is reached when... whamo! Another big bang springs to life.
Hold on... We have a race of beings, could be us, who have evolved to exist around a black hole and have grown with it. Each time it merges with another black hole, they simply move away until things settle down. The most wonderful result would be the first people to actually witness a big bang. Sweet.
I have gleaned this information and presumed this story from joyfully watching SFAI Thx a bunch Big I.