“Dark King” Silvers Rayleigh is the former first mate of the Roger Pirates, known as the “Right Hand of the Pirate King”. He’s extremely powerful, easily one of the strongest characters introduced.
Shakky vouches for his strength by saying that he is “100 times stronger than all of you boys”, referring to the Eleven Supernovas.
Furthermore, when Garp was informed Rayleigh may be on Sabaody Archipelago, he told his men not to confront him, he reasoned that the Marines should not confront two legends, Whitebeard and Rayleigh at the same time.
Due to his phenomenal strength, he was able to fight Admiral Kizaru equally and he even managed to scratch the admiral. However, Rayleigh himself has admitted that he is not as young as he used to be, and can tire in battle. This may mean when he was in the prime of his strength he may have been even stronger than when he matched Kizaru, a true testament to his strength!
Jinbe, a former Shichibukai who was used to seeing Whitebeard, was later shocked to see Rayleigh in person. Eustass Kid himself even states that Rayleigh was “a Legend”.
Another glimpse of his strength is seen when he seemingly snatches off Camie’s exploding slave collar and tosses it into the air before it could self destruct.
He has tremendous physical strength despite his elderly age. He is powerful enough to kill several Sea Kings with his bare hands while swimming in the Calm Belt.
Rayleigh is shown to possess great mastery of Haki, and made use of all three types while teaching Luffy about them, and training him in the basics.
He has mastered Haoshoku Haki (Conqueror’s Haki) to the extent that he can render a specific target completely unconscious. He is able to do this without adversely affecting anybody else near the initial target. He disabled an entire hall room of hostiles with this power, save for the Kid Pirates and Heart Pirates.
Only very strong and determined individuals can resist from being knocked unconscious. One of Trafalgar Law’s crewmen was very close to being knocked out, and even Law and Eustass Kid were sweating slightly after enduring the blast.
Busoshoku Haki (Armament Haki) allows Rayleigh to create a force similar to an invisible armor around himself. Rayleigh has the ability to bypass the powers of a Devil Fruit user, touching the “substantial body” beneath whatever protection the fruit provides as seen when he used Busoshoku Haki to kick and redirect an attack from Admiral Kizaru.
Recently, it is shown how Luffy is mastering Armament Haki in Wano. In the Prisoner Mine, Luffy wipes out the Pleasures in the sumo ring with ease as he works on repelling his opponents with Busoshoku Haki without touching them, like what Rayleigh did when he first demonstrated the Haki to him.
Armament Haki Rayleigh showed him was really Advanced since he could hit or deflect objects without even touching it.
Kenbunshoku Haki (Observation Haki) can allow Rayleigh to sense the emotions and nature of others. The strength and mastery Rayleigh has over this kind of Haki is also shown by the fact that he can sense people all over the island he is currently on while most people can sense only in their immediate vicinity. Rayleigh also used Kenbunshoku Haki to dodge an elephant’s attack without directly seeing the elephant.
Recently the “Luffy Gear 4 Vs Rayleigh” filler scene in Episode 870 reminded us that Rayleigh is still one of the strongest beings in the entire One Piece World. Luffy Gear 4 Bounceman was just a punching bag to Rayleigh.
He probably could have one shotted Luffy just like Kaido did if he was a bit more serious. This could mean that Rayleigh is close to Yonko level if not Yonko level!