“He's not the most intelligent agent in UNATCO, but he's cunning, strong and steadfast. Gunther has given his loyalty to UNATCO and those he considers to have proven themselves worthy of respect. That does not apply, by the way, to any wet-behind-the-ears kid with a cool sense of fashion and no scars — i.e., you. Gunther recognizes that the world is divided into the strong and the weak. The strong make the rules; the strong enforce them. He is not concerned overmuch with right and wrong, and in fact considers the concept unrealistic. He's given his allegiance irrevocably to UNATCO in return for power: both having his personal strength augmented and being a member of a world-changing organization. His loyalty to Anna Navarre borders on the dog-like. He holds no regard for death, either his own or others. The only thing he truly fears is that his augmentations may become outdated, rendering him weak and unable to perform his duties. ”
- description of Gunther Hermann to the player, Deus Ex
Gunther appears in Deus Ex: The Icarus Effect, a prequel novel to the game series. The young Hermann is described as a man in his late twenties, with pale blonde hair, ice-blue eyes, a thick neck and physique as a body-builder. At this time his only enhancement was his left hand. Sometime in the early 2020s, Hermann served in the German counter-terrorist unit GSG 9 . Hermann was not satisfied by the way they worked. After getting into trouble, he was contacted by the Tyrants – an Illuminati-backed black-ops group - who offered to make his problems go away in return for his services. Gunther was more than willing to join the Tyrants. Gunther told teammate Ben Saxon (one of the two lead protagonists) that the reason that made him join the Tyrants was because their commander Jaron Namir told Gunther that they wouldn't let things like the law get in the way of justice. During his time with the Tyrants, Hermann was involved in many assassinations, including the assassination of Garrett Dansky, chief executive of Caidin Global. During that mission, he murdered Matt Ryan, the superior and close friend of Secret Service Agent Anna Kelso, one of the book’s protagonists.
During the first major operation, Gunther, Saxon, and Scott Hardesty are sent to kill Mikhail Kontarsky, an administrator of the Russian committee on Human Augmentation, in the Hotel Novoe Rostov in Moscow. They find Kontarsky in a secret room, speaking to a mysterious figure, "Janus." Ben hesitates, and Hardesty kills Kontarsky from a sniper perch across the street. Hermann and Saxon are both tased and knocked out onboard their private plane. When they awake, Jaron explains that one of the two is not loyal to the group, and the two must fight to the death to determine which. He throws a handgun with a single round, and the two fight over it. Ben eventually gets the pistol, but he refuses to kill Gunther. Jaron says that the fight was just a test between the two, and that the round was a blank. After that, he, Saxon, and Hardesty are sent in Virginia to kill Scott Temple and anyone currently in his house. During a fight with Ben Saxon onboard a Tyrant plane, Gunther is shot in the eye with a taser slug and breaks several bones in his torso, physically scarring him.
Their next mission is in Geneva, Switzerland, where the Tyrants plan to assassinate Bill Taggart of Humanity Front on the steps of the Palais de Nations, making him a martyr for the anti-augmentation cause and push for a vote on UN regulation. Gunther is driving a car-bomb when Anna recognizes him as Matt Ryan's killer. She jumps onto his van and struggles with him, nearly getting knocked off, though she gets the upper hand and grazes Gunther in the head with her handgun. He swerves the car and knocks Anna off, shortly before sliding into the Rhône River and detonating the car bomb. Gunther disappears. At the end of the book, a young Morgan Everett and Lucius DeBeers are meeting in person in Paris in front of the Eiffel Tower. They recollect about the operation in Geneva: Bob Page, Morgan's apprentice, has recovered Gunther Hermann from the Rhône River. He would live, but needs extensive augmentation across his entire body, and his newfound respect for Majestic 12 will probably keep him from working for the Illuminati anymore.
In 2052, Gunther worked for UNATCO, and he is resentful of the arrival of a new breed of nano-augmented UNATCO agents, whom he fears will replace his generation. Like fellow UNATCO mech and friend Anna Navarre, Gunther has sacrificed social acceptance for enhanced mission performance by undergoing first-generation mechanical augmentation. He deeply resents "the infinite power of nano-augmentation," as well as the agents who utilize them. While his augmentations grant him strength and speed far beyond that of normal men, they have also left him disfigured. His ability to upgrade his biomechanical mods is also finite, and they are prone to the degradation of any constantly operating piece of machinery. He receives significant wear in his line of work, and is often returning to Dr. Jaime Reyes for a tune-up. The player can read an e-mail from Jaime Reyes quoting an anonymous e-mail from a mech-aug (clearly Gunther, judging from the bad spelling) in which he expresses concern that he and those like him will be "sld at flee markets... old gray golems for scareing the children".
The player's first real encounter with Gunther - apart from the training course, where he acts as the weaponsand demolitions instructor - is optionally rescuing him from the NSF terrorists at the base of the Statue of Liberty in the first mission. Whether the player does this (and whether the player arms Gunther, or makes him run back to base unarmed) sets the stage for how Gunther feels about the player throughout the game. Gunther is next met in the break room, where he is complaining to Navarre that the staff have a plot against him. The player next meets Gunther at the end of the Hell's Kitchen mission, where Gunther takes over for JC. Gunther is next seen at the LaGuardia Airport, overseeing the UNATCO peacekeeping occupation. Afterwards, he can be found near the entrance to the Battery Park subway station, if JC gets that far after UNATCO raids the 'Ton. Later in the game, Gunther is sent to kill JC Denton, whom he engages in a French cathedral, linked to the Knights Templar, in Paris. The player is given the choice between calling out Gunther's killphrase or attempting to reason with him. If he is killed, Walton Simons tells JC that he only sent Gunther because he was tired of him complaining about wanting to avenge Anna Navarre and wanting a tune-up. It is possible to avoid fighting Gunther Hermann several ways. Gunther is supposed to be killed here, and, like Anna, while it's hypothetically possible to go around him, the game treats him as dead after Paris.
- "That will be adequate."
◾ "No. I wanted orange. It gave me lemon-lime."
◾ "I do not make mistakes of that kind."
◾ "I want to be the one to execute Lebedev."
◾ "Again they ignore me. Again they think they have a better punishment for a traitor than a shotgun to the head."
◾ "No, I cannot forgive. No... not the killing of Agent Navarre. I will follow you. Denton, I will get you!"
◾ "I see you, a thief on the roof. My new satellite link has both infrared and the x-ray spectrum. I see your heart beating. I see you are afraid."
◾ "Manderley has assigned me the peacekeeping occupation of this district."
◾ "I-I-am not a machin-"
◾ "THAT is a gentlemen's agreement."
◾ "Agent, open the door!"
◾ "I believe I will enjoy this."
◾ "Unglaublich!" (Unbelievable in German)
•Hermann is apparently paranoid; an overheard conversation between Gunther and Anna Navarre reveals that his large fingers may also hinder his ability to operate soda machines, although he insists that the "maintenance man" switched the cans of orange soda in the machine with lemon-lime, as "he knows I like orange." When the player returns to the ruined UNATCO base in the sequel to Deus Ex, Invisible War, a conversation with an NPC confirms that Gunther was indeed a victim of conspiracy by the maintenance men.
•Gunther makes several mentions during the game of his wish for a head-mounted gun, or "skul-gun," that would allow him to kill without using his arms. When exploring the UNATCO HQ ruins in the second game, it can be learned that a skull-gun shipment was received by UNATCO a little while after Hermann's demise. In Deus Ex: Human Revolution, an email can be found discussing the practicality of skull-guns for mech augs.
•According to dialogue from Anna Navarre, Gunther has killed close to a thousand people during his service with UNATCO; in fact the two seem to have a running competition of enemy kills. Taking into account his career before UNATCO, his kill-count must be well over a thousand.
- Gunther seems to be inspired by the character Batou from Ghost in the Shell.