|Political and military information|
- "Nothing can kill the Chief."
- —A young John-117 refers to Mendez
Senior Chief Petty Officer Franklin Mendez is a legendary UNSCDF NCO who was involved in the training for every Spartan soldier in the Spartan-II and Spartan-III programs. His career is extensive and he has earned numerous medals and commendations fighting the Covenant and the Insurrection.
 SPARTAN-II training
He was the Spartan-II's training leader during their first years on Reach in 2517 until 2525. He trained them in the aspects of combat as hard as any Marine when they were only at the age of 6. His military training was punctuated with in-class strategy sessions with Déjà.
In the beginning of their training, Mendez and his training instructors used electric batons to discipline trainees. However, his trainers would occasionally use rifles with tranquilizer rounds to incapacitate the trainees (those that would eventually make up Gray Team) who attempted to escape. Eventually, the Spartans, Spartan-117 in particular, grew to look up to Mendez as a solid, unmovable force in their life. They had great respect for him, perhaps even to the extent of seeing him as a father figure.
 SPARTAN-III training
After the SPARTAN-IIs graduated, Mendez was slated to train the next class of Spartan-IIs, but the program was delayed by Dr. Halsey due to issues with viable candidates. Mendez requested reassignment to active duty. Over the next six years, he fought the Covenant on five worlds, won two more Purple Hearts, and was promoted to Senior Chief Petty Officer. Mendez was then recruited by Colonel James Ackerson to assist Kurt Ambrose, formerly known as Kurt-051, in running the SPARTAN-III Program. He trained three SPARTAN-III companies at Camp Currahee on Onyx from 2531 until 2552. He was originally skeptical of the job, comparing the behavior of the trainees to that of the schoolchildren in Lord of The Flies.
When he arrived to train Alpha Company, Kurt Ambrose mentioned that Mendez had aged very well, that he had a trim chiseled body from "ironwood", with hair that was now silver, deep creases around his eyes and that a set of ragged scars that ran from brow to chin. By 2552, Kurt still found him to be surprisingly fit and agile, noting he moved like a soldier thirty years younger and wondered what kind of Spartan he would have made.
 Battle of Onyx
- Main article: Battle of Onyx
While training the final batches of SPARTAN-III Gamma Company on October 31, 2552, Mendez and the other UNSC forces on Onyx came under attack by Sentinels. He, along with SPARTAN-III Team Saber, Tom-B292, Lucy-B091, and Kurt Ambrose were virtually alone on the planet, and were forced to hide from Sentinels for several days, until Kelly-087 and Dr. Halsey eventually arrived, followed shortly by Blue Team; Fred-104, Will-043, and Linda-058. Mendez assisted them in fighting all the way to the core of Onyx, where he eventually evacuated to Shield World 006, held in a slipspace bubble in Onyx's core, along with the other survivors.
 Shield world and later career
At the funeral for the Spartans who died in combat, he read an excerpt from his favorite book: an account of the Rain Forest Wars called A Soldier's Tale: Rainforest Wars. While in the shield world, Mendez began to reflect upon his role in training the Spartans. He also took note of Halsey's discomfort with the SPARTAN-IIIs he had helped train, confronting the doctor about this on several occasions.
After Mendez and the other survivors had reconnoitered the sphere for some time and established a base camp in a Forerunner city, Lucy-B091 discovered several Huragok which helped the human survivors contact the ONI ships outside the slipspace bubble and eventually bring the sphere into normal space. Mendez and the others were then taken to a debriefing in HIGHCOM Facility Bravo-6 aboard the UNSC Port Stanley. Mendez, along with the surviving SPARTAN-IIs, were present in the Voi Memorial unveiling ceremony on March 3, 2553.
 Personality and traits
Mendez is a strict, by-the-book military man and thus has a solid sense of duty and honor. He also rarely allows himself to display his emotions (for example, John-117 very rarely had seen him smile). When he heard of the destruction of the Spartan-IIIs, he kept his face stony, holding his feelings to himself. His total need for discipline and order off-sets many of his new acquaintances, however those who know him well (namely the Spartan-IIs, particularly John-117 and Kurt Ambrose) have a respect and relationship with him that can be compared to that of the connection between father and child.
- Before teaching the Spartan-IIs, Mendez was a hand-to-hand combat and physical training DI (drill instructor) as a Chief Petty Officer.
- Halo: First Strike has a potent reference to Mendez, in which Dr. Halsey, while accessing Colonel Ackerson's files on the SPARTAN-III Program, discovers a file called CPOMZ (short for Chief Petty Officer MendeZ), followed by a 512-character alphanumeric string. This file was the first clue as to Mendez's whereabouts as well as the SPARTAN-III Program, which was later confirmed in Halo: Ghosts of Onyx.
- On Reach, he had a Warthog variant which was equipped with a rack of Argent V missiles instead of the standard M41 Vulcan Light Anti-Aircraft Gun.
- He read the book Lord of The Flies sometime in his life and compared the Alpha Company recruits to the kids in the book in a private conversation to Kurt-051.
- Mendez gave John-117 his quarter back at the final moment they met. He recalled that John broke a few of the trainers' fingers when they tried to take the coin from him.
 List of appearances
- Halo: The Fall of Reach (First appearance)
- Halo: First Strike (Mentioned only)
- Halo: Ghosts of Onyx
- Halo: Evolutions - Essential Tales of the Halo Universe
- Halo: Blood Line
- Halo: Fall of Reach
- Birth of a Spartan (Possibly)
- Halo: Glasslands
- ^ Halo: Glasslands, page 208
- ^ a b c d Halo: Ghosts of Onyx, page 69
- ^ Halo: Blood Line
- ^ Halo: The Fall of Reach, "chapter 4"
- ^ Halo: The Fall of Reach, page 38
- ^ Halo: The Fall of Reach, page 35
- ^ Halo: The Fall of Reach, page 99 ("The only constant in the universe")
- ^ Halo: The Fall of Reach, page 99
- ^ Halo: The Fall of Reach, page 101
- ^ Halo: Ghosts of Onyx, page 129
- ^ Halo: Ghosts of Onyx, page 365-366
- ^ Halo: Ghosts of Onyx, page 378-379
- ^ Halo: Glasslands, page 73
- ^ Halo: Glasslands, page 37-40
- ^ Halo: Glasslands, page 382-389
- ^ Halo: Glasslands, page 401-403
- ^ Halo: Glasslands, page 414
- ^ Halo: The Fall of Reach, page 69
- ^ Halo: The Fall of Reach, page 95
- ^ Halo: Ghosts of Onyx, page 70