Naruto is not short of plot holes. But Madara’s Reanimation is perhaps the biggest.
Naruto has a lot of plot holes, despite being considered one of the greatest shonen stories. Madara Uchiha is a controversial villain who is loved by some for his extraordinary strength and by others because of how easy he was to manipulate into killing thousands of people. Although it is confusing to see Masashi Kishimoto create a genius character like Madara only for Zetsu to play him so easily is also confusing. But the plan to cast Infinite Tsukuyomi contains so many logical inconsistencies that his reasoning eventually stopped making sense.
It would have been better to present Madara as a totally evil character, with the goal to destroy the world. For better or worse, however, it is a hallmark of the series to give villains a tragic background and motivation to gain sympathy from fans. Even though there are many issues with this character, including the fact that he wasn’t the series’ final villain, his reanimation is absurd. This may be the most significant loophole in this series.

How did Madara get back from the dead
Kabuto Yakushi used a forbidden Jutsu technique to bring back Madara and other fallen Shinobi. His strength was so strong that even in a reanimated body, all the Shinobi could not stop him. Madara then forced Obito, who was already fully revived, to perform the Rinne-Rebirth Jutsu. He not only recovered a living body but also retrieved his Rinnegan making him the most formidable enemy in the entire war area. The Five Kages’ combined strength could not even scratch the Uchiha, the most powerful in history.
What Was the Plot Hole, and How Was It Solved?
When you look back at all the characters that died and were then revived using a forbidden Jutsu it becomes clear that the reanimated versions of them are exactly the same age as the original. Madara was over 100 years of age when he died. But, he was revived in the form of his younger self (roughly his 30s). He was then revived and became stronger than ever. Madara also had identical Rinnegan eyes when he awoke just before his death.

Madara would not have been able to cause such destruction if he were in an elderly man’s body. But, to make the villain more terrifying, he had been in a young man’s body. It is fair to say that this plot hole was a significant one, as the series did not explain it.