1. Medic Dou: Initially appearing as a helpful ally, Medic Dou was actually a spy for Orochimaru. He later turned the tide of war by learning sage arts and commanding a large army of revived shinobi.

2. Konan: Former student of Jiraiya and member of the Akatsuki. Though initially overshadowed by Yahiko, she surprised everyone during a battle against 6 trillion paper bombs, showcasing her impressive abilities.

3. Suigetsu Hozuki: Once an experiment of Orochimaru, Suigetsu joined Sasuke's team and showed great bravery in facing the Eight-Tails to protect his comrades, despite his initial timid appearance.

4. Black Zetsu: Previously believed to be an incarnation of Madara Uchiha, Black Zetsu was actually the child of Kaguya Otsutsuki. He manipulated the entire series and ultimately defeated Madara.

5. Jugo: Initially seen as a simple character, Jugo possessed hidden power and bore the Rinnegan. His true strength surpassed expectations.