As a former member of the Roger Pirates, captain of the Red Hair Pirates, and one of the Yonko in the New World, Shanks is known to be one of the four strongest pirates in the world.
Not much is known about Shanks’ powers and abilities in detail. Blackbeard, who had the powers of the destructive Gura Gura no Mi Fruit and the evil Yami Yami no Mi Fruit chose not to fight Shanks saying “he is not strong enough to fight him yet”.
Until now Shanks has shown mastery over two types of Haki: Haoshoku Haki and Busoshoku Haki.
When Shanks and Whitebeard clashed with their weapons, the “heavens” above them split, hinting at the incredible Busoshoku Haki that the two Yonko had imbued in them.
During the Battle of Marineford, he imbued Busoshoku Haki into his sword in order to block a Logia attack from Akainu.
Shanks can use Haoshoku Haki, an ability that only one in a million people can use!
After saving Luffy from a Sea King, Shanks frightened it off with a single angry glare using this ability.
Later, while Shanks was boarding Whitebeard’s ship for their meeting, a large amount of Whitebeard’s crew (experienced men who have survived in the New World) lapsed into unconsciousness and the ship itself began to take physical damage from Shanks’ mere presence.
Whitebeard’s men attributed this to his superior Haki. Oda mentioned in a SBS that Shanks could have knocked out all 100,000 pirates and fishmen opposing the Straw Hats during the Fishman Island Arc with his Haoshoku Haki (Luffy managed to overwhelm 50,000).