Rean exited the Dimensional Realm and returned to the city with Gustav. Since he was in the Transition Realm, he didn't need to pass through the gate. Instead, he just flew over it and headed straight to where Gustav lived before. The city was still enormous, so Gustav didn't really know it all. Rean had to return to somewhere close to where he lived so that Gustav could show him the way from there.
"So, where to?"
Gustav looked around before he dashed away, saying, "Through here, uncle Rean."
Rean laughed after seeing that. He could have just flown with the kid, but the kid completely forgot that.