Necklace | One Piece | Dracule Mihawk's Crucifix

Dracule "Hawk Eyes" Mihawk is a world-famous pirate who holds the title "Strongest Swordsman in the World". Formerly one of the Seven Warlords of the Sea (the first revealed and formally introduced) until the group's dissolution, Mihawk has since become one of the founders of Cross Guild, alongside his former Warlord colleague, Sir Crocodile.

Mihawk is a tall, lean, and muscular man with a fair complexion and short-cropped, jet-black hair that is slicked back, as well as a short beard, mustache, and sideburns that point upwards in a "V" shape. His nickname comes from his strangely colored eyes: red in the manga, yellow in the anime, which resemble a hawk's eyes due to the concentric ring present around each pupil.

Mihawk wears black-and-red, ornate clothing with a golden (white in the manga) crucifix pendant that hides a little dagger, which gives him the appearance of a Spanish swordsman. 

(from Fandom One Piece Wiki)