Itami lost his family at the age of thirteen when his brutally abusive father was killed by his wife in self-defense. Although she was cleared of criminal charges, her feelings of guilt and regret shattered her sanity; she began to believe that her husband was still alive and longed for his return. One night, Itami couldn't stand it anymore and brutally confronted his mother with reality; but instead of making her come to her senses, it made her attempt suicide by self-immolation. She was saved from death and placed into a mental institution, where Itami left her to languish until many years later (see Plot, below).
At about the same time (though it is not specified whether this occurred before or after this family tragedy), Itami met the much older politician Tarō Kanō, who had suffered a professional setback at that time. Mutually interested in the mangas the other was reading, Itami and Kanou began exchanging their favorite series; it is claimed that this was the point where Itami became a full-blooded otaku. Around that same time, Itami met a girl from a lower school class and a fellow otaku, Risa, who would eventually marry him not out of love, but rather for mutual convenience.
Itami graduated from a mediocre college with mediocre grades. After finishing officer training, where he ranked second from the last (since the person before him was injured), he became a Second Lieutenant. His work performance was considered barely acceptable, so a frustrated superior ordered him through Ranger training. Even though he almost failed several times, he still managed to finish by keeping his head down while troubling his buddies. His only remarkable achievements during that period, as noted by his superiors, were his ability to run from any trouble coming his way so fast that nobody could catch him, and that he infected a sizable number of his fellow troopers with his otaku obsession. After that, Itami transferred to Narashino (a Special Forces Garrison) for some reason and was expected to end his days as a Second Lieutenant.
During one training exercise which scenario was to rescue a hostage being held by 50 SFG troopers, Itami became an only trainee who managed to succeed in the mission. He took advantage of the “T this is training” mindset of the SFG members and launched a surprise attack by taking the SFG commander, who was inspecting the training exercise, hostage. Itami then proceeded to cruelly pluck the remaining strands of the SFG commander’s hair one after the other. this action forced SFG members, driven by the desire to protect the thinning strands of their commander’s hair, to release their own hostage. Consequently, Itami received both a commendation and “special considerations” from the SFG commander and was forcibly enrolled in a series of comprehensive long-term training courses from which he could not possibly escape. 
Due to his status as a member of SFG, Itami was also forced to undergo paratrooper training courses. And despite his fear of heights, Itami successfully obtained a paratrooper badge by being shoved off an aircraft five times. If the Ginza incident hadn't happen, Itami would probably have been forcibly enrolled into free-fall courses. 
|!!!Spoilers!!!: This contains information that can spoil parts of the story not shown yet.|
When the gate first appeared, Japanese citizens were attacked by an unknown hostile enemy force. Though he does his part, Yōji was much more worried about the fact that he wouldn't be able to buy any Doujinshi due to the attack, rather than the fact that a hostile army came out of nowhere and was killing people. During the incident he directed local police forces in defending citizens who had fled inside the Imperial pPlace. Due to the Ginza Incident, he was praised by the minister of defense for his actions during the Battle of Double Bridge and was promoted to First Lieutenant.
Yōji later went on the be given command of the Third Recon Team, sent to recon the Special Region. During his first incursion into the region, he rescues Tuka Luna Marceau from an Elven village attacked by the Flame Dragon, before going on to encounter Lelei la Lelena in a column of refugees, who were fleeing from the Flame Dragon. Along the way, Yōji meets Rory Mercury, shortly after she slaughters a group of bandits. Soon afterwards, the column was attacked by the Flame Dragon. At this point the Third Recon Team first displayed their firepower to the residents of the Special Region, blowing off the arm of the dragon- which was considered practically invincible by the Special Region residents- with a Panzerfaust 3 rocket launcher, forcing the severely wounded beast to flee.
In the aftermath of the dragon attack, Yōji was left with the decision of what to do with the orphans, wounded, and elderly that could not be taken care of by the rest of the villagers. In the end, he chose to take them back to the base camp at Alnus Hill, cleverly turning off his radio, so that he was forced to bring them in unannounced. He suffered some backlash with his officers, resulting in paperwork and various chores that he had to do by himself, but ultimately was allowed to keep the refugees and even introduced them to Japanese culture and food (which they loved).
Later on, the refugees - namely Lelei - found the corpses of dozens of Winged Dragons, which scales fetched a hefty sum for their trade. Deciding that it was better if the refugees could provide for themselves, rather than having to rely on the JSDF, Yōji escorted Lelei, Tuka, and Rory to Italica - a major agricultural and trading city that was important to the Empire - where they could sell the scales. Unfortunately, Italica was also at the epicentre of a battle between knights-turned-bandits and the Rose Knights, led by Piña Co Lada.
Though there were only 4 of them, Piña Co Lada and her comrades were able to fend them off, but only for another day. Soon after the battle, Yōji and his recon team reached Italica, having observed the smoke coming from the castle earlier, and approached to ask what had happened. Piña Co Lada was intent on making them her allies, but unfortunately got off on the wrong foot, when she slammed the door in his face unknowingly and unwittingly as she opened it. Putting that aside, Yōji awakened and learned about the bandits, and proposed to join forces in a temporary alliance - a way of gaining their trust and showing that it was better to be on the same side. (Rory misunderstood and believed he was doing a show of force to intimidate them, exasperating Yōji.) It is here, before the sunset, where Yōji made a call back to base for a special favor of assistance...
When night time came, Piña Co Lada's tactics and her own misconceptions about Yōji's goodwill put Italica in grave jeopardy, when the bulk of their force attacked the East Gate, which was completely different from her expectations. Yōji, despite understanding that Piña Co Lada was trying to make them into a suicidal decoy, still expressed his interest in helping her, and waited for her to call on him. When that didn't work, Rory's eagerness for battle gave him the excuse to chase after her towards the Eastern Gate. During the chase, Yōji set off a flare, revealing that he had called in helicopters to help deal with the bandit attack. The UH-1J and AH-1S Cobra Attack Helicopters decimated the attacking bandits with gunfire, rockets, and TOW missiles, all whilst blaring "Ride of the Valkyries" from loudspeakers. At the same time, Rory and Shino Kuribayashi joined the fray, killing dozens of bandits before Itami extracted the two of them, shortly before the helicopters fired on the bandits near their position ruthlessly, and totally wiped them out in an extreme style of absolute annihilation. In the end, Yōji was recognized as a hero by the Countess of Italica, and the townspeople were forever indebted to the JSDF.
Yōji eventually talked to Piña Co Lada, whereupon a treaty was made between the JSDF and the Empire (non-officially). In it, he wanted to take a few of the prisoners back to the refugee camp, and didn't demand anything spectacular besides allowing tax-free trade for the JSDF and affiliate citizensd (such as Lelei). This was only made in the presence of Piña Co Lada, Hamilton, and Grey, however, which resulted in Yōji's abduction by the rest of the Rose Knights Order in a total misunderstanding on the way back to the base. In order to remedy and reconcile with the JSDF, Piña Co Lada and Bozes Co Palesti accompanied Itami and his team back to the Alnus Hill Base, and began to set up peace negotiation with the Japanese Government.
Following the JSDF victory at the Siege of Italica and the signing of the treaty between the JSDF and the Empire, Itami was summoned to report to the Japanese National Diet on the dragon attack on the convoy from Coda Village along with Sgts. Shino Kuribayashi and Akira Tomita. Also summoned were Lelei, Tuka, and Rory, as Special Region residents. In spite of attempts by some members of the Diet to paint the JSDF as at fault for the 150 civilian casualties in the incident, all three Special Region residents maintained that Itami's actions saved the lives of three quarters of the Coda refugees.
Before and after their appearance at the National Diet, Itami, Kuribayashi, and Tomita escorted Tuka, Lelei, and Rory through Tokyo. It soon became apparent that foreign agents were tailing the visitors from the Special Region. This prompted Itami to use the unconventional technique of evading pursuit by hiding out in the apartment of his ex-wife, Risa. Risa would later accompany Itami and the rest of his group to the Hakone. An incident occurs at Hakone, resulting in a firefight between JSDF, CIA, Russian, and Chinese special forces, which is joined by Rory in the manga and anime, resulting in numerous casualties to all factions involved. Itami, Kuribayashi, Tomita, and his charges escape Hakone and immediately make a return to the Gate in Ginza. Before they arrive, Risa announces the time of their arrival at the Gate, resulting in a massive crowd that foils further foreign attempts to capture the Special Region residents. At the same time the Japanese prime minister is forced to resign under allegations of corruption of himself and other party members. This action later results in the CIA's involvement in the firefight who then are forced to pull out of the country and presumably deny any responsibility for the incident.
After returning to the Special Region, Itami starts to notice Tuka is becoming increasingly psychologically traumatized by the loss of her father, to the point where Tuka tries to deny this fact by viewing Itami as her father. At the same time, Itami is approached by Yao Ha Dushi, who attempts to convince the JSDF to aid her in the destruction of the Flame Dragon that killed many of both her and Tuka's people. The JSDF, however, are unable to aid because of diplomatic issues with the Kingdom of Elbe.
At the same time, negotiations with the Empire break down after the Third Recon are sent to assist with earthquake relief in Sadera. During a meeting with Emperor Molt Sol Augustus, Crown Prince Zorzal El Caesar enters leading a group of his sex slaves on a leash. Zorzal states one of them is a Japanese woman named Noriko Mochizuki, captured in the early moments of the invasion, before the decisive defeat of the Empire at Ginza. This infuriates Itami, who strikes Zorzal, knocking him to the floor. Zorzal orders his guards to kill Itami and the rest of his recon team, but they are easily dispatched with gunfire and bayonets. Itami then has Kuribayashi beat information about any other Japanese slaves out of Zorzal, an order she carries out with extreme enthusiasm.
After Kuribayashi brutally beats Zorzal, knocking out a few of his teeth while breaking two of his fingers, Itami asks Zorzal for the locations of the captives again, this time at gunpoint. At this point, Tyuule places herself in between Itami and Zorzal, refusing to let him come to any further harm. Shortly afterward, Noriko and (presumably) the other slaves are released, except for Tyuule, who refuses to leave Zorzal. Little does Itami know, she is planning to drive the JSDF to destroy the Empire as revenge for the devastation of her homeland.
The morning after Itami's departure, the JSDF send a warning to the Empire. That day, two JSDF F-4 Phantom fighter jets bomb the Senate, destroying the unoccupied building as a warning to the Empire.
After the incident at the capital, Itami discovers that Tuka's condition has worsened, and decides the only way to save her is to kill the Flame Dragon, and agrees to aid Yao, deserting with a vehicle and a large supply of Panzerfaust 3s and C-4 explosives, joined by Rory, Tuka, and Lelei. Itami joined the dark elves of Roldom Canyon, training them in the use of the Panzerfausts before venturing with them to the summit of Mount Tube, where the nest of the dragon was located.
Itami laid the C-4 charges under the nest while the dragon was out hunting, however, he was interrupted when the dragon arrived and attacked his party. The dark elves attempted to use the Pzf-3s against the dragon, but with literally only the most basic of training, all of them either failed to properly arm the rocket, or scored only non-fatal hits on the dragon. All of the elves except Yao were killed in the engagement with the dragon.
The dragon was finally slain when Lelei used her magic to levitate the swords of the fallen dark elves and launch them at the dragon. This provoked it into charging right onto the C-4 charges Itami had laid moments earlier. Tuka used her lighting magic to create a massive electrical discharge, detonating the C-4 and killing the dragon in the explosion.
Meanwhile Rory was engaged in close combat with rival apostle Giselle, who had managed to tame the dragon's two offspring as servants. Giselle incapacitated Rory, intending to kidnap her and force her to marry the underworld goddess Hardy. Giselle ordered her dragons to attack Itami and the rest of his party, but they were saved by the timely arrival of the JSDF, who killed both dragons with artillery and air strikes. Giselle was captured and presumably taken into JSDF custody.
After returning to Alnus, Itami was penalized with a 2-month suspension of pay and a reassignment to Special Region Resource Investigation Team 101, placing the Third Recon under the command of Sgt. Major Sōichirō Kuwahara, at least until a new officer was assigned. While Itami was lightly penalized, Itami was given a wide list of honors and commendations. The Defense Minister of Japan gave Itami a grade one commendation for saving Noriko, King Duran of Elbe gave Itami a letter of thanks and a noble title, and the Dark Elf elders gave Itami the title of honorary chieftain, a pile of adamannite, and ownership of Yao.
Itami and the investigation team, which consisted mostly of Special Region locals Rory, Lelei, Tuka, and Yao travelled east from Italica towards Rondel. In the manga, they first visited Crety, where they neutralized the threat of a disease similar to a "zombie virus" of popular culture originating from an ancient ruin.
Sometime after returning from the resource expedition, Itami and the others went to Rondel to help Lelei with becoming a master. When Lelei and her sister Arpeggio El Lalena duel each other, in the anime the duel occurs before Lelei's presentation). Itami asks Rory why they are dueling since he is concerned with the property damage it may bring. Itami is later informed by Grey about assassins being sent to kill Lelei and helps protect her during their stay in Rondel. Itami later learns from Shandy that Zorzal had been sending assassins to kill Lelei, and preparing for a second raid.
Itami tells the brass about his plan, and the brass agrees to carry it out, and while he goes to rescue Piña it is suggested by the brass to also save the emperor if possible. Itami later enters the throne room with Rory and Lelei to confront Zorzal. Zorzal sends a giant orge after them, but it is quickly killed. Zorzal later attempts to fight Itami, who responds by shooting the floor right in front of him. Itami explains to Zorzal that the JSDF is always watching, that his life can be taken at any time, and to stop sending assassins at Lelei. Itami later leaves with Piña, and on the way, also pick up the rest of his squad.
After the peace negotiations, Itami does not attend Piña's coronation, since the Doujinshi convention was starting again. Back in Japan, Itami makes his way to the convention, only to bump into Rory, Tuka and Lelei. A police officer later escorts them out of the scene in his police car. Itami's ex-wife Rika passes by and is startled that Itami is in the car, and Itami cries, stating that he just wanted to go to the convention.
Itami's relationship with his female associates can be described as a paternal affection. While he deeply cares about the girls, he has as yet shown no romantic interest towards them, mostly because several of them are - in terms of physical growth (if not of chronological age) - still adolescents and underage, but also because of his own sense of decency.
- Tuka Luna Marceau: While Itami is very fond of Tuka, her apparent perception of him as a substitute father hinders him in taking that relationship to a deeper level. What Itami is unaware of is that Tuka keeps calling him "father" just to conceal her bashfulness, as her feelings for him actually run much deeper.
- Lelei La Lalena: Itami believes that Lelei is actually too young to really consider a serious romance with him, and that her genius intellect is highly incompatible with his simple personality.
- Rory Mercury: Itami actually finds Rory - both in appearance and personality - attractive. However, with her physical development put on hold by her immortality and his wariness of Japan's child protection laws, he does not want to involve himself in what he considers an immoral relationship. Despite that, he is very fearful of Rory as she often forces herself onto him to point that she nearly rapes him.
- Pina Co Lada: At first, their relationship is a professional give-and-take for the sake of the peaceful relationship between the Empire and Japan. Pina eventually falls in love with Itami after he rescued her from Zorzal's grip, however Itami is wary of the political repercussions such a relationship would cause. His effort to avoid getting into a relationship with Pina is also being hindered by Hamilton, since she tries her best to make Pina have Itami as her consort.
- Yao Ro Dushi: She is in love with Itami and considers herself his slave. While he has largely come to accept her in that role, he doesn’t make any romantic advances as he considers this an abuse of authority. Itami is also horrified of the fact that Yao wants to have a baby with him due to the heavy responsibility as a father, but luckily, Rory won't allow this to happen.
- Akira Yaginada: Itami and Akira shares some rivalry toward each other as Akira sees Itami as a happy-go-lucky slacker who managed to achieve the rank of First Lieutenant through luck rather than hard work like him. However, they still manage to give each other respect and Akira willing to help Itami as he goes as far as blackmailing Duran to let the JSDF go through Elbe to support Itami to kill the Flame Dragon, although he also does this for the sake of exploiting Elbe Kingdom's untapped resources like rare earth, uranium or other minerals that are too advanced for the Special Region native to exploit.
- Deliah: Deliah behaves submissively toward Itami, much like Yao, as she often refers him as Master Itami. In return, Itami shows some degree of care toward her.
- Giselle: Giselle resented, but deeply feared Itami after he killed the Flame Dragon with 72 kg of C4 and the JSDF eliminated two of her offspring ancient dragons. However, her resentment vanished after Itami gave her delicious meals to quell out her hunger. After the end of the civil war, their relationship had improved but she still bugs Itami for more delicious foods and drinks.
- Zorzal El Caesar: Itami and Zorzal are enemies since the moment of their first meeting, first because of Itami's dislike of Zorzal's cruelty and arrogance, and subsequently because of his treatment of Noriko Mochizuki. Despite his facade of bravado, Zorzal in turn deeply fears Itami after Itami uses a sniper to make it clear to him that he will not be safe from the JSDF's retribution. Itami often refers to Zorzal as an idiot who never knows his place in the world. Despite their hostility, Itami and Zorzal never face each other in the Imperial Civil War and Itami was not in the scene to witness his death or end his pathetic life.
Skills & Abilities
It was initially written as a joke by Itami’s superiors who sarcastically wrote in Itami’s documents that he is an expert at marksmanship, hand to hand fighting, psychological warfare, airborne skills, diving, explosive use, and so forth. The detail of Itami being “proficient at detecting danger before anyone else” is another way to say, by his superiors, that Itami is good at running away. While a majority of them are false, Itami seems to display good capabilities in skills that his superiors joked about, such as psychological warfare and close combat.
- Keen Instincts: Itami is proficient at detecting danger before anyone else, and act appropriately based on that.
- Ranger & Special Forces Training: As a member of the JSDF, Itami is in top physical condition. He is a skilled combatant with both firearms and melee weapons. He is a Ranger, meaning he can perform grueling tasks where others would normally give up; a further testament to his abilities. During his return trip to Japan to brief the Diet, it is mentioned that Itami is not just a Ranger but also a member of the Japanese Special Forces.
- Regeneration: After making a pact with Rory, Itami has been granted regenerative powers. All his injuries manifest on Rory instead, which her Healing Factor can take care of.
- Superior Intelligence: Itami has shown superior intelligence to the average person's. He makes accurate assessments about situations and acts accordingly. He also managed to learn the language of the Special Region quickly and well enough to understand most conversations. His decisions are helpful in battle and when dealing with people.
- Psychological Inducement: Itami appears to be proficient when dealing with psychological warfare. This was made evident when Itami had met Zorzal a second time as he made the prince believe that the JSDF is easily capable of omnipotently killing him. This later caused a heavy trauma on the former crown prince as this experience, coupled with his already unstable sanity, would leave him suspectible to hallucinations centered about the ease with which the JSDF could eliminate him.
- Leadership: Despite his immense reluctance to assume a position of responsibility, Itami has proven himself as a natural leader whenever the situation demands it. Furthermore, he shows great responsibility to those who serve under him, and is able to competently assign their assets in a conflict situation.
- Escape & Evasion: Itami is said to be an expert at E&E (Escape & Evasion), more so than anyone in the SFGp. During training nobody could locate him even after the training ended. Combining this with Itami's keen instincts, it is said he is always a step ahead of everyone else.
- Genre Savvy: As an unrepenting otaku, Itami displays an uncanny ability to correctly assess his and others circumstances from the perspective of the reader/viewer, serving greatly to his advantage.
- Itami's surname shares the same pronunciation and Romanized spelling as the city of Itami in Hyogo prefecture, home to the JGSDF Central Army headquarters.
- In Light novel 8, we learn Itami is afraid of heights when he takes a wyvern ride with Yao. He has her steer while he holds on to Yao.
- He hates paperwork.
- He seems to have a soft spot for children.
- His motto in life was “Eat, sleep, play, repeat. And the life in between.”
- The phrase in one of his favorite manga was ‘The only time you are alive is when you are resting’
- According to himself, he sucks at geography.
- He also likes to say "Hobby first, work after".