The Medal of Everlasting Life is an enchanted magical medal that saves and protects the wearer from injury, harm and death. It is an important object in the movie seeing as the town of San Ángel was attacked by the bandit king Chakal and his army of banditos looking for it.
The medal is black in the shape of a heart. It has grey spikes around it and green fabric. It also has a white skull with red eye and nose sockets in the middle, in between two green wings.
The Medal of Everlasting Life gives the wearer immortality and invulnerability from physical injury and harm, so long as the person keeps touching or wearing the medal. The wearer can also not feel pain or exhaustion/fatigue. The Medal can also reawaken a mortal being from a coma, as shown when it awoke María.
Originally created by Xibalba to serve an unknown purpose, this magic magical medal has since fallen into the hands of many people throughout time and history. At one point in time Chakal got his hands on the medal by fighting Captain Mondragon and therefore making himself invulnerable and invincible until Xibalba retrieved the medal back.
Chakal spent 10 or 20 years looking for it. At the beginnging of the story timeline ten years ago when Xibalba and La Muerte made their famous wager on November, 2, The Day of the Dead. Xibalba secretly gave the magical magic medal to his chosen champion Joaquín Mondragon, whose father war hero Capt. Mondragon had been killed by the bandit king Chakal. Joaquín kept the medal secretly hidden for ten years until the bandit king Chakal and his army of banditos attacked the town of San Ángel looking for it. Joaquín gave it to Manolo to protect him and after the battle it was returned to Xibalba.