Have you guys noticed that whenever Akatsuki members are about to die they always use their last resort. Sasori used his 100 puppet performance. Deidara blew him self up as his ultimate art. Itachi used Susano'o. Kisame merged with Samehada. Konan trapped Tobi with her massive barrage of explosive tags for five minutes. Pein used his Samsara of Heavenly Life Technique to revive the villagers. Orochimaru used his body transfer technique and showed his true form. Kakuzu was in his Shinzo mode which was like his true form. Hidan died in his ritual form. The other members of the Akatsuki are still alive. So based on my analysis, here is my prediction. When Tobi or Zetsu are about to die then we will see there last resort jutsu.