As ancestors of orphans trained by Albert Bolden and Ignacio Cardona, Miguel and the woman guarded the Koh-i-Noor for years using their skills. As part of their duty they killed anyone who got close, including some Assassins. One of their victims was a young Assassin recruit Stephen Heggenes.
In August 2018, at 21:45pm, 3 days before Resurrection Day, Miguel and his fellow guard spotted the Assassins Arend Schut-Cunningham and Kiyoshi Takakura on a nearby hill. Under false pretenses, Miguel greeted Arend in Spanish but switched to English when Arend replied in kind. The two guards then attacked the Assassins, however Miguel and the woman were no match for the two being easily defeated. Miguel was then promptly kicked off the hill.
Before the Assassins could continue beating them, the Instruments of the First Will arrived via helicopter to retrieve the artifact. The Instrument Jasdip Dhami, recognizing the blood of his former student Heggenes, tortured Miguel by ripping out his fingernails with a pair of pliers. When their position was bombed by the Instruments, Miguel walked through the fire in a last ditch attempt to prevent the Dhami from escaping with the artifact, he was killed after Jasdip sliced his head into half with a Hidden Blade.
After the guardians were killed and the Instruments escaped with the Koh-i-Noor, Miguel and the woman were buried by Arend in the mass-grave.