Sengoku possesses a Mythical Zoan Devil Fruit that allows him to turn into a Buddha and attack using shockwaves. To date, he is the only Marine with the power to use all the three Haki types. Undoubtedly, with these abilities, he is capable of rivaling the Yonko.
Having killed Whitebeard, stolen his Devil Fruit, and then acquired all his territories and his allies, he solidified himself as one of the strongest people on the seas and gained a bounty of 2.246 billion berries. The newest additions to the ranks of the Yonko are Monkey D. Luffy and Buggy.
The Admirals and the Yonko are certainly not equal in power and the former will always reign supreme as the strongest in the One Piece world, which Oda once again showed in the previous chapter.
Mihawk has fought many friendly duels with Shanks(one of the Yonko) and they both use swords as their weapon . Mihawk is a better swordsman than Shanks ,but Shanks has powerful haki and many other attacks . Though my point is that Mihawk has the potential to beat a Yonko.
During the Summit War, Whitebeard used his power to decimated Akainu during their fight, in fact one of his quakes was able to harm Akainu even when parts of his body were made of magma.
Garp is easily the most powerful Vice Admiral in the Marines, and rivals or exceeds the power of the known Admirals and Fleet Admirals. After then-Admiral and future Fleet Admiral Sakazuki (also known as Akainu) killed Ace, Fleet Admiral Sengoku held Garp down to prevent him from killing Sakazuki in revenge.
Best Power: Gura Gura no Mi
Out of all the pirates in the One Piece world, Whitebeard is the only man who could match Gol D. Roger in a fight, making him the strongest Yonko.
8/14 Marco The Phoenix
The Gorosei considered him to be one of the very few men capable of stopping Blackbeard, putting his name in the same breath as the Yonko of the world. Marco was already in the running for the position of a Yonko so there is no denying that he has the potential to become one.
Following this, he was declared the 5th Emperor of the Sea, however, Luffy was never truly recognized by his peers. As such, his defeating Kaido and finally rising to the position of a Yonko is quite significant. This time, Luffy is globally recognized as one of the Yonko.
Big Mom is the oldest Yonko in the One Piece story.
It is pretty obvious that when Doflamingo could not stand up to the power of Gear 4th Luffy, there's no chance of him surpassing someone like Garp in terms of strength.
Garp is a Vice-Admiral of the Marines. Being their strongest known member in history, there's no denying that Garp is capable of taking on Kaido. He's previously fought against the likes of Rocks, and even Gol D. Roger.
he can beat those two yonko for sure. His power and haki and stamina are way too strong for these two yonkos.
1/10 Kaido
He is known to be extremely difficult to hurt and throughout his life, only Kozuki Oden and his nine retainers have managed to hurt him. Kaido has the power of an unnamed Devil Fruit that allows him to transform into an eastern dragon at will. Without a doubt, he's the strongest in the story right now.
To counter Katakuri's Future Sight, comparable Observation Haki or much greater raw speed is needed. King possesses the required speed. However, to reach such quickness, he has to lower his otherwise unparalleled durability. King beats katakuri with high diff and it's not even a debate.
In terms of strength, Luffy is already at the level of the Yonko. While he may not have awakened his Devil Fruit, he's taken his Haki to the level of the Yonko, being able to use the advanced form of all three Haki types, which is something that no other Yonko can do at the moment.
He does now. That is perfection in a sense that he mastered how to control it.
He demonstrates proficient usage of Busoshoku Haki, being able to injure Luffy several times, bypassing his rubber body. He was also seen crushing Chinjao's uniquely shaped head with a Haki imbued punch 30 years ago, by hardening his fist and turning it obsidian black to increase the damage inflicted.
Ofcourse he can use all forms of haki.
Could 2 people have the same devil fruit? This is probably a stupid question, but since it only requires a single bite of a devil fruit for the powers to be transmitted, could 2 people take 1 bite of the same fruit, and both get the powers? Nope, only the first one can have its ability.
At the end of every One Piece episode, Luffy proclaims, "Kaizoku ou ni ore wa naru!," translating literally to "I will be the Pirate King" in English. His desire to become Pirate King is the basis of the series, and Oda makes sure that the audience knows how important this goal is to Luffy.
During Sanji's cooking battle in a Loguetown Arc filler episode, it was mentioned that some fish species that should not exist in the East Blue were found due to ocean currents, which made Sanji certain that the All Blue exists.