It’s not a Century King, it’s basically a Millennium King.

Yuran’s Ace: Millennium Shield

It appears after monsters for a year, a decade, and a century are brought out. It’s an Iron Wall monster with an incredible DEF that can stop even “Blue-Eyes White Dragon” in its tracks!

Yuo’s Mysterious Scheme… The Duel That Reveals The Truth Behind It Will Air On July 25th, 2021!!

Source: Weekly Shonen Jump