Leo Fitz

"You're gonna suffer for what you've done, and I plan on being a very big part of that."

- Leo Fitz to John Garrett Leopold "Leo" Fitz is a Scottish-born Level 5 S.H.I.E.L.D. agent and scientist. He is a brilliant engineer, and inseperable from his research partner and best friend, Jemma Simmons. He, along with Simmons were recruited to Coulson's Team by Melinda May and worked with them on all of their missions. While on the team, Fitz became very good friends with teammate Grant Ward. During the S.H.I.E.L.D. Civil War, he became jealous of Simmons' friendship with Agent Antoine Triplett. Fitz was an active participant in hunting for John Garrett and the rest of the Centipede Project. He was shocked by the revelation that Ward had been a member of HYDRA all along, and refused to believe it, resulting in several arguments with Simmons and the rest of the team. Fitz was captured by HYDRA along with Simmons, and met Ward again. When Ward was ordered to kill them, Fitz fruitlessly begged Ward to not, and was dumped into the ocean in the Bus's Medical Pod with Simmons. They survived the fall but were trapped on the ocean floor. Fitz devised a plan using the Pod's oxygen bottles to get them out of the pod and to safety, but their was only enough oxygen worked for one, and while confessing romantic feelings for Simmons, he saved her. However, this resulted in him spending a long period of time without oxygen, possibly causing brain damage.

Early Life
"It's like magic. But, it's-- it's science."

- Leo Fitz

As his accent indicates, Leopold Fitz was born in Scotland, United Kingdom. A genius-level engineer, whose only other relative is his mother, Leo Fitz attended the S.H.I.E.L.D. Academy of Science and Technology along with his equally intelligent best friend, bio-chem expert Jemma Simmons. Among their instructors at the academy were Professor Vaughn and chemical kinetics advisor, Professor Franklin Hall.

Fitz and Simmons graduated from the academy three years early, and Fitz would have been happy to spend all of his time in a lab. However, at the urging of Simmons (and against the advice of Professor Vaughn), the pair put in for a field position.

Field Work
"I said there would come a moment when we would regret the decision to go in the field. I didn't think that would happen in week one."

- Leo Fitz to Jemma Simmons

Fitz and Simmons were recruited by Agent Phil Coulson to be the science crew for a new team he was putting together. Stationed on the Bus, the pair have designed specialized equipment and compounds on the fly in emergency situations.

Their first foray into the field involved the case of Michael Peterson, a man in danger of exploding due to his use of the volatile Centipede Serum. Peterson was saved in part by Fitz's invention, the Night-Night Gun, which contained specially designed bullets that delivered a Centipede counter-agent to Peterson.

Fitz first faced danger in the field in Peru, where the team was investigating an 0-8-4. After facing Peruvian rebels and an armed takeover of the Bus, Fitz found it hard to concentrate at first, but later came through for the team, using his D.W.A.R.F.s to activate the old HYDRA weapon in order to regain control of the Bus.

When Simmons was infected with an alien virus passed along from a Chitauri Helmet, Fitz risked contamination and death in order to help save his friend.

Operation: Overkill
"I am every bit the S.H.I.E.L.D. agent you are!"

- Leo Fitz to Grant Ward

Sometime later, Fitz and Agent Grant Ward were assigned by Agent Victoria Hand to infiltrate the border of South Ossetia and destroy an enemy weapon known as the "Overkill Device". Despite his inexperience (and a few missteps), Fitz showed quick thinking, ingenuity and courage during the assignment and was essential to the successful completion of the mission.

Agent Fitz' noteworthy actions include the timely activation of a Localized EMP Device when his and Agent Ward's lives were in jeopardy, gaining the trust of the locals (specifically Marta and Vladimi) and the modification of the Overkill Device's core, which allowed him to neutralize the enemy soldiers weapons.

Among his missteps were the vastly overpaying the locals for safe transit across the border and bringing a sandwich (prosciutto and buffalo mozzarella with a hint of pesto aioli) into the field while being tracked by dogs.

Field Work 2
Fitz was forced out of his niche and into field work when the team got separated during a mission in Italy where they were chasing a Cybertek Prosthetic Leg bought by Ian Quinn. He and Skye were the only ones left who could continue the chase. As Fitz waited for the others after he sent a tracking beacon, Skye went inside Quinn's mansion and was shot twice in the stomach.

He blamed himself for this as the team went to S.H.I.E.L.D. Trauma Zentrum in Switzerland and learned that Skye's wounds were fatal. Phil Coulson refused to accept this diagnosis and gave him and Jemma Simmons Level 10 access to files on his resurrection. Fitz figured out the location of the Guest House and went with Coulson, Grant Ward and John Garrett to find GH.325. When he did, he took it to Skye for Simmons to inject her with it, fully healing his teammate.

Secrets
Unfortunately, that was the only sample he retrieved and Jemma Simmons berated him for it because the Guest House was destroyed. He and Simmons continuously monitored Skye and took blood samples in hopes of duplicating the miracle drug, but the Bus did not have equipment sufficient enough for the job. Also, Phil Coulson ordered the research must stay in house. Meanwhile, Lorelei and Grant Ward hijacked the Bus and enthralled Fitz. Simmons began to look at him differently.

Fitz witnessed as Skye became an official S.H.I.E.L.D. agent and watched as Ward killed Thomas Nash. He became upset though as Simmons was called to the Hub to be a consultant on Deathlok. So they could communicate secretly about her findings on GH.325, Fitz put in a secret phone line. However, he found that Melinda May already had one. He told Skye about this just as it was realized that the Clairvoyant was a S.H.I.E.L.D. agent. May chased Fitz hoping to shoot him with an I.C.E.R. before he could reveal her secret, but he locked himself away before she found him. While Phil Coulson, May, Skye, and Fitz had a four-way argument about secrets, Victoria Hand redirected the Bus to kill Coulson's Team.

S.H.I.E.L.D. Civil War
Fitz watched Phil Coulson and John Garrett battle the S.H.I.E.L.D. UAVs chasing Garrett as it became assumed that Victoria Hand was the Clairvoyant. When they reached the Hub, Fitz's invention, the Mouse Hole, kept them from being captured. Garrett accidentally revealed he was the Clairvoyant and an agent of HYDRA, greatly upsetting Fitz for his betrayal. Garrett offered Fitz a place in HYDRA while Fitz swore vengeance. During the Battle at the Hub, Fitz hid but his contributions saved his teammates' lives when it was needed.

Fitz began to notice the attraction Jemma Simmons had for Antoine Triplett, but he distrusted him since he worked under Garrett. When the team and Triplett left the Hub to go to Providence, Fitz talked with Simmons, but she let him know that things have changed.

Fitz went with Phil Coulson, Triplett and Simmons to Portland to apprehend Blackout. He discovered Coulson's past relationship with Audrey Nathan, and talked Coulson into using her as bait to stop the Fridge escapee. Fitz modified the stage lights of the building using the Gamma Power Reserve designed by Bruce Banner causing Blackout to explode. When the group returned to Providence, they found the Bus and half the team gone.

Betrayed
Fitz helped Coulson research their whereabouts, but he questioned Coulson's leadership after their experiences in Portland. Looking for a skillet to help Simmons make pancakes, Fitz found a message left by Skye, "Ward is HYDRA," just as Simmons found Agent Eric Koenig's body. When Simmons' autopsy report proved Ward was the killer, Fitz had a tantrum that had to be calmed by Coulson. Meanwhile, Maria Hill led Colonel Glenn Talbot to Providence, causing Fitz and the team to relocate to Los Angeles.

Eventually, Coulson's Team found John Garrett and Grant Ward in Havana, Cuba. Grant Ward found Fitz and Jemma Simmons spying on them as Centipede Project prepared to leave for New Mexico. He brought Fitz and Simmons aboard the Bus where Fitz activated an EMP Joy Buzzer that fatally injured Garrett. Fitz begged Ward to let Garrett die, but Garrett told Ward to kill Fitz. Fitz and Simmons became cornered in a Medical Pod and Ward ejected them off the Bus into the Atlantic Ocean.

Best Friends Forever
"At least we still have each other." "Good, 'cause the last thing I want is for things to change." "Fitz...It's too late for that."

- Jemma Simmons and Leo Fitz

Now trapped with Simmons on the seabed 90 feet down, Fitz jury-rigged a beacon transmitting a distress signal on an unmonitored S.H.I.E.L.D. frequency, all with a broken arm. When Simmons woke up, he explained the situation to her; there was no way out of the container, and they were going to die.

However, some time later, Simmons devised a way to break the glass keeping out the water. With some hope of escape, the pair worked the problem further. Eventually, with the detonation ready to go, Fitz handed Simmons a one-time use air supply and explained that there wouldn't be enough for the both of them. After a tearful display of affection from Simmons, Fitz hit the trigger for the explosion.

Not willing to give up her closest friend, Simmons dragged Fitz with her to the surface where they were rescued by the timely arrival of Nick Fury, responding to their makeshift distress signal. While Simmons was placed in a Hyperbaric Chamber to recover from the pressure sickness, Fitz was examined by a medical team. His brain went without oxygen for an extended period of time, although his heart was still beating.

Fitz ultimately survived the ordeal. However, when asked about him later, the fully recovered Simmons would only say "he's alive" with no further context, implying that Fitz suffered brain damage from oxygen deprivation.

Personality
Like his best friend Jemma, Leo is known to be an attractive nerd on his profile for S.H.I.E.L.D., though he is somewhat socially awkward. Fitz also has a strange affinity for monkeys. He is also a genius-level weapons/technology specialist which has assisted S.H.I.E.L.D. many times through-out his career. Fitz was even able to fully repair Lorelei's Asgardian Collar (made of Asgardian metal), greatly impressing Sif with his intellect. He also has a great sense of humor, teasing Ward behind his back (in a mockery Southern accent), and planning to prank Skye. He is also a good actor, and easily impersonates an American tourist.

In spite of his lack of combat skills, Fitz impressed the more experienced Ward with his remarkable bravery and quick thinking during their mission together. Fitz believes deeply in the friendships he creates: being upset when Skye appears to have been secretly working with Miles Lyndon, actually crying when John Garrett revealed himself as HYDRA , as well as having a rare angry fit and emotional breakdown when Ward was revealed to be a murderer and a HYDRA mole. In return, Fitz is very loyal to his friends, is miserable when he was unable to save Skye from Quinn, and trusts Simmons with his life.

While Fitz is devastated at Ward's betrayal, he is the only one on the team that still insists that Ward is redeemable, as Fitz believes that people are never "born evil." He is the only one who still tries to reason with Ward and implores him to let Garrett die and abandon HYDRA. Thus, Fitz is also very forgiving and understanding of others' problems, shown when he quickly forgives Skye for being so secretive about Miles Lyndon, claiming that everyone "makes mistakes." He also instantly forgives Coulson for knocking him out with a punch, understanding the situation. As Simmons grows closer to Triplett, Fitz remains suspicious of him, though he does learn to trust him later on.

Fitz also tends to go through with his promises and threats: he promised Garrett that he would suffer for what he had done, and he (Fitz) plans to be a "very big part of that." By electrocuting and nearly assassinating Garret shortly thereafter, Fitz manages to keep his word.

Fitz-Simmons Designs
"I'm engineering, she's bio-chem."

- Leo Fitz

Allies

 * Family
 * Unnamed mother
 * S.H.I.E.L.D. - Allies
 * Nick Fury - Former S.H.I.E.L.D. Director
 * Maria Hill - Former S.H.I.E.L.D. Deputy Director
 * Victoria Hand † - S.H.I.E.L.D. Superior
 * Felix Blake - S.H.I.E.L.D. Colleague
 * Eric Koenig † - S.H.I.E.L.D. Colleague
 * Coulson's Team - Teammates and Friends
 * Phil Coulson - S.H.I.E.L.D. Director and Team Leader
 * Jemma Simmons - Best Friend and Love Interest
 * Antoine Triplett - Former Rival
 * Melinda May
 * Skye
 * S.H.I.E.L.D. Academy of Science and Technology
 * Anne Weaver - Former teacher
 * Franklin Hall - Former teacher
 * Professor Vaughn - Former teacher
 * Akela Amador - Enemy while under HYDRA Coercion, now Ally
 * Michael Peterson - Enemy while under HYDRA Coercion, now Ally
 * Elliot Randolph - Ally
 * Sif - Ally

Enemies

 * HYDRA
 * John Garrett † - Former S.H.I.E.L.D. Superior
 * Grant Ward - Former Teammate
 * Jasper Sitwell † - Former S.H.I.E.L.D. Superior
 * Raina
 * Ian Quinn
 * Kaminsky
 * Camilla Reyes
 * Cybertek - Enemy Organization
 * Carlo Mancini †
 * Lorelei - Enemy turned Enthraller

Trivia

 * Fitz is apparently a fan of the long-running, British Sci-fi television show,  as he has a model of the Doctor's beside his bed.
 * Fitz has a distaste of corpses contaminating his work space after accidentally eating a liver from a dead cat that Simmons was working on.
 * Fitz is the first and only known person that Agent Melinda May has pranked after she became grim and seemingly unemotional.
 * Fitz greatly impressed Sif herself, who admitted that he was "quite clever."
 * Fitz can do a perfect American accent, due to watching a lot of American TV in his childhood. He also does a mockery Southern accent while teasing Ward behind his back.
 * Fitz is the only member of Coulson's team that still believes that Ward is redeemable, and not truly evil. He is also the only one that tries to reason with Ward and implores the latter to let Garrett die and abandon HYDRA.
 * Fitz is the first member of Coulson's team that almost kills the "Clairvoyant", John Garrett. Thus, Fitz becomes, quite possibly, the one Garrett hates the most, since the latter immediately ordered Ward to kill him.
 * Fitz's favorite sandwich is: prosciutto, buffalo mozzarella, and a touch of pesto aïoli on what looks like a baguette.

Behind the Scenes

 * The relationship between Fitz and Jemma Simmons is based on the relationship between Jed Whedon and Maurissa Tancharoen.
 * Due to his popularity, Leo Fitz will appear in the mainstream Marvel Comics universe.
 * Fitz's obsession with monkeys was inspired by Iain De Caestecker's real life love of monkeys.