1. Kimimaro's Loyalty to Orochimaru: Kimimaro, the last survivor of the Kaguya clan, devoted himself to Orochimaru after being saved by him. He fearlessly fought against Lee and Gaara, although his illness prevented him from delivering the final blow. Overall, Kimimaro did not experience any major defeats. 

2. Minato Namikaze's Speed and Skills: Minato Namikaze, the Fourth Hokage of Konoha, was renowned for his incredible speed.

Few ninjas could match his agility, allowing him to escape unfavorable battles. He fought evenly against A and defeated Tobi before sacrificing himself to save his son. Minato never faced true defeat. 

3. Hashirama Senju's Domination: In his era, Hashirama Senju held immense power and authority. He advocated for peace during the Five Kage Summit, and even Madara Uchiha required his agreement to take action.

However, the circumstances of Hashirama's death remain a mystery. 

4. Itachi Uchiha's Genius and Loss: Itachi Uchiha, with his Mangekyou Sharingan, was an exceptionally skilled ninja. His superior intelligence allowed him to analyze and adapt to defeat opponents. Itachi possessed the ability to foresee the future, making him a formidable adversary. His only defeat came intentionally when he chose to lose to his brother Sasuke.

If he had fought seriously, he could have defeated Sasuke easily. 

5. Shino Aburame's Defeat in Boruto: Shino Aburame, a proficient insect user in Konoha, had never experienced significant defeats until his battle with Mitsuki in Boruto. The newcomer outmatched him, teaching Shino a valuable lesson. This unexpected defeat showcased that even experienced characters can be overcome.