Nagato Uzumaki, also feared as Pain, was the leader of the Akatsuki and was being controlled by Obito to collect the chakra of all the tailed beasts. He was by far the best villain in Naruto and had one of the best character arcs ever seen for a villain.
1) Sasuke and Naruto
The rivalry between Sasuke and Naruto is arguably one of the most popular in the series. They pushed each other to the absolute limits and became some of the strongest characters towards the end of Shippuden.
Itachi Uchiha:
Itachi Uchiha is the single most powerful character in the Naruto Universe. Masashi Kishimoto named himself Itachi Uchiha. He unlocked his power at a very early age, for example, unlocking his Sharingan at a very early age. When he was 11, he joined Anbu black ops.
Jiraiya. Jiraiya was an exceptionally competent shinobi, and he was the only member of the Legendary Sannin who could actually beat Itachi. He was trained by the Third Hokage, and learned how to use Sage Mode while training with the toads of Mount Myoboku.
Kaguya Otsutsuki was an ancient deity who was responsible for the first flow of Chakra reaching human beings. One of the most powerful beings, as all the other Otsutsuki are, she is definitely someone who can beat Madara.
1) Isshiki Otsutsuki
He is stronger than the combined force of Naruto and Sasuke. Although his powers were nerfed because Jigen's body was a weak vessel, he overwhelmed Naruto and Sasuke, and almost killed the latter. Sasuke was able to give a good fight to Isshiki, but he can't fight him alone.
1) Madara Uchiha
This man was able to tame tailed beasts which really showcased his strength. As a child, Madara was able to awaken his Sharingan with one Tomoe in each eye. His mastery of the Sharingan and jutsu capabilities makes him far stronger than Kakashi.
Hashirama Senju
This one is a pretty obvious choice, but it's worth restating. The legendary First Hokage, Hashirama Senju was known as the "God of Shinobi" for a reason. He was the only one capable of defeating Madara Uchiha during the latter's early life.
On the one hand, Jiraiya seems to have the durability and ninjutsu to match Kakashi. On the other hand, Jiraiya does not seem capable of matching the Sharingan. The two both have incredible strength, and Jiraiya's sage mode may give him a distinct advantage.
kakashi will put up a very good fight but would lose to itachi like 7 times out of 10 he would win 3 times because of his performance against asura and deva path of pain who were the strongest paths of pain.
obito uchiha (broken hero)
He Wasn't Totally Evil
Though he loved the taste of his own blood and its noted several times that his chakra itself can be seen as evil, Madara himself wasn't a bad person — he just let circumstances in life lead him down an evil path.
Naruto and Sasuke are arguably the most powerful characters by the end of the Naruto Shippuden anime, so it goes without saying that Might Guy would stand no chance against Naruto in his Sage of Six Paths mode, or against Sasuke using his Rinnegan.
He is dubbed by most to be the strongest shinobi in history. Sasuke himself admitted this fact. In the end, while Sasuke may not be able to beat Naruto, even with his perceived weakened state in Boruto, the two did become friends again. A combination of powers that are said to be able to destroy the entire world.
Tsunade's raw power is terrifying and Jiraiya has been on the receiving end of her wrath. However, the Pervy Sage can beat her in battle. It's true that Tsunade has Strength of a Hundred jutsu, which gives her temporary invincibility.
Black Zetsu was central to one of the biggest shocks in Naruto during the 4th Great Ninja War. It was he who stabbed Madara Uchiha in the back and struck him down when he was at the pinnacle of his powers. Zetsu was then revealed to be the perpetrator of the plan to bring Kaguya back.
It is easy to see that Sasuke supplants Madara in every category except for chakra reserves as the latter was the jinchuriki of the Ten-Tails. However, Sasuke is far ahead in all the other categories. Consequently, Sasuke is undoubtedly the strongest Uchiha in Naruto.
3) Madara Uchiha
At the height of his power, he was able to slaughter entire groups of ninja, take on the Kage, and slice the tops of mountains off! Alone, Boruto wouldn't stand much of a chance.
Kakashi's own double Mangekyo Sharingan power is far superior to Guy's eight gates. Even though Guy almost touches the speed of light, Kakashi's Kamui is instantaneous. He's fast enough to blitz even Kaguya Otsutsuki, and as such, Might Guy stands no chance.
Final thoughts. There is no doubt that Kakashi is quite strong despite the loss of Sharingan. He is by no means weak and can hold his ground against tough opponents. Whether it be his ninjutsu, taijutsu, or shuriken jutsu, Kakashi has mastered them all.