When Shanks met Whitebeard, he praised his Haki. Similarly, Oda himself has highlighted Shanks's Haki on many occasions, and the feats that he's shown cannot be matched by many in the One Piece world.

Shanks worked with the government, possibly as a Holy Knight, indicated by the mark on his arm. Shanks may have capabilities of immortality and regeneration due to his past association. Shanks's ...

Shanks stopped the war at Marineford. He also met with the Five Elders. Shanks' Haki is strong. One Piece Film: Red showed his character. His role is crucial in the Final Saga.