77 Rings

The 77 Rings (７７) was a challenge held for knights in Windknight's Lot during the Middle Ages, featured in the first part of the JoJo's Bizarre Adventure series, Phantom Blood.

Known to freeze the blood of any man, the challenge served as a training method. Only five knights in history have completed it.

The Trial
The challenge consists of crossing a 10-kilometer mountain range via stairs and roads. On the way, the knight must not only surpass cliffs and rivers, but also defeat 77 opponents in a series of fights to the death. Each of the 77 opponents carry a bracelet or anklet, which must be taken by the knight and worn for the duration of the challenge. Individually, these rings aren't heavy, but the combined weight of all 77 rings is more than a hundred kilograms. All but five knights have failed the challenge, with most having their skulls collapse from the rings' pressure. Of the five winners, Bruford was the only one to not possess a strong build, preferring to instead utilize his Danse Macabre Hair.

Trivia

 * The Phantom Blood PS2 game cuts the narrator's explanation of the 77 Rings, but contains a extra mode called 77 Rings Knights Mode. In this mode, the player must defeat 77 Knight Zombies in a single battle. The mode is split into two variations, Ripple Warriors and Living Corpses; up to six additional characters are unlocked for each time the mode is cleared, while a seventh can be unlocked afterward by clearing another extra mode, Dio Mode.
 * Winzaleo, Eijkman, and Caineghis make an appearance in the game as part of an alternate final chapter. Dio Brando revives the three and takes Father Styx's body to defeat Jonathan. The three knights also appear in the game's Extra Battle Mode, and are given their own profiles in Profile Mode. Ironically, they cannot be unlocked in 77 Rings Knights Mode.