You are all wrong! The osaka arc is not over. Right when they got transferred back to the room, Gantz becomes a dick again, and made everyone to come back to Osaka to fight the real Nuri (the one that we've seen is only the duplicate that is constantly channelled by the real Nuri's power, thus giving him the power to regenerate many many times) similar to the Tae arc where the team has to come back for another mission in one night.
When everyone back to Osaka, they find out that there are totally 6 separate forms of Nuri, and his real name is Pain. They only defeated one.