Viper's Creed

AGS Blademen were deployed to pursue a Megasoma Bugmech en route to Daiva City. The Megasoma puts up a tough offensive against the AQS Maneuver-Blades, nearly forcing the army to intervene after the Blademen had sustained casualties to eliminate the armed Bugmech. One of the Blademan operatives, Saiki Cryde, decides to sacrifice his Manuever-Blade by self-destructing it in order to blow up the Megamsoma taking a section of a highway along with it. In the end, Saiki was forced to give up most of his pay for the highway's repairs despite being able to eliminate the threat.

Haruki Oguma, the only son of AGS President Fuyuhiko Oguma, is selected to be an AQS Blademan operative despite his father's wishes for him not do so in order to prove that he can protect Fort Daiva City and its people by himself and not by his father's influence. His presence brings some doubt to the other veteran Blademen, including Saiki, due to his ties with the company's president. During an AGS operation to hunt down Gellis Bugmechs, Haruki receives orders to immediately withdraw. Despite this, he disobeys them and hunts down the Gellis with Saiki accompanying the young Blademan as they were able to defeat squads of Gellises on their own.

Saiki gets blamed for the killing of a local man after he had fired on the Blademan in an anti-Bugmech operation that resulted in civilian casualties. In the course of hiding from the police, Saiki is given shelter by an old friend, from his war days, named Doc while Kariya tries to obtain information covertly on the culprit responsible for framing him. During her investigation, she finds out that one of their own could have been the real shooter in the death of the homeless man and framed Saiki in his place. She enlists the assistance of Haruki to help her locate the culprit while Norma and Rudra are on the scene to capture the culprit for monetary gains.

After a young elementary school student was kidnapped from a monorail by an unknown man, Norma works alone to provide ransom money to save her from her captors. However, the car used to transport her was planted with a Ticker bomb by an Acromantis Bugmech. When Norma was wounded by a gunman in the outskirts of Daiva City, she reveals to Kariya and Saiki that the girl's name was Marie and she was her only daughter during their time together as homeless refugees after escaping from war before she gave her up to adoption due to lack of necessities needed to provide care for her and was recruited as a Blademan operative in order to ensure that Norma can provide it to her daughter.

Police arrest Rudra for being the main suspect responsible for the assassination of a public official by using a sniper rifle-armed Maneuver-Blade mecha despite him being present with the other AGS personnel during an anti-terrorist operation. Being released from police custody with the intervention of AGS officials, the blonde man has surmised that the main culprit responsible for the attack before his detention on the official was someone from his past. He finds out that Maya, an ex-war buddy of his from his World War III days as an anti-government guerrilla after an attempt was announced on President Oguma.

When Haruki invites Saiki, Kariya and Gharib to eat with him in a local Asian ethnic restaurant for dinner, the four AGS personnel find out that the owner is subjected to a huge debt. However, Gharib finds out that the one sent to collect the debt on the restaurant was an ex-soldier who had trained under him during Gharib's day as a military officer when the soldier's hands were disabled after the bald man saved his life by shooting the armed landmine. Determined to save the restaurant and do something about his life once more, Gharib decides to help the owner's daughter to move on from the past and assist her in her cooking skills.

An anti-AGS riot turns sour when Rudra threatened to use force to settle it after a bombing incident was credited to Hounds, a group of supposedly anti-PMC terrorists when mainstream news media claim that they were simply just extremists not out to kill. Haruki has doubts over the claims and visits Ulla Chiaki, the main leader of Hounds and a friend of Haruki who tells him that he and the others didn't plant the bomb in the mall. However, public pressure over pro and anti-Hound groups has forced AGS to conduct an anti-terrorist mission. The Blademen were deployed to locate them, only for their systems to be hacked in order to give Ulla and the others the chance to escape.

Theresia Strauss, AGS official, suggests to Fuyuhiko Oguma that Haruki was the most likely culprit for yesterday's failed mission. Doubt begins to surface from within the Blademen unit when Norma suggests that a double agent was responsible for their recent anti-Hounds operation. Haruki encounters Ulla, but is seen speaking with Theresia in an abandoned church. He later returns to AGS headquarters and finds a hidden garden of flowers created by his father to honor his late mother. Haruki was assassinated in the building after his encounter with Ulla with Kariya and Saiki being the only witnesses to his death.

AGS goes out to the public by using Haruki's death to further propagate anti-Hound operations and to promote AGS, deploying the Viper unit to a Hound safehouse before the military intervenes to arrest them instead. The unit was later blamed for massacring the Hound members who had surrendered as terrorists in a news report, forcing Saiki and the others to hide from public view as AGS security forces are mobilized to hunt them down before the police and the military apprehend them themselves. Saiki was able to escape being killed after he attacked intruding masked men, who are revealed to be military commandos.

Ulla Chiaki, the leader of the Hound, appears on national television and accuses the Vipers of killing his fellow members. Jimmy, an AGS technician, assisted Kariya in escaping from AGS custody with the assistance of a hacker named Ageha. The Viper members gathered together in an abandoned warehouse off the grid in order to avoid being caught by AGS security forces and law enforcement. In order to find out who was responsible for framing them as terrorists, Saiki leads the Vipers in storming AGS headquarters to reacquire their Maneuver-Blades. Norma is seemingly killed to hold off VTOL jets by ramming her Maneuver-Blade against them after being wounded by Utsugi, one of the kidnappers who had been the mastermind of kidnapping her daughter.

Theresia and the renegade military faction were able to seize control of AGS with help from Ulla, who had been assisting them all along from the shadows. A Bugmech was launched against the public to further blame Saiki and the other Blademen as "terrorists". Saiki and the other Blademen, including Kariya, remain in hiding while receiving assistance from an unlikely ally. A covert operation was launched by renegade soldiers to kill the Blademen in a mob-owned restaurant. Gharib stays behind and offers his life on the line to assist his AGS Blademen colleagues in escaping with their lives. Rudra was later wounded and killed by military snipers after his Maneuver-Blade malfunctions.

Saiki faces off against Ulla in his custom Maneuver-Blade prototype before he was severely wounded to the point that he was blinded. Kariya assists him in guiding him to the Daiva Broadcasting building by using his World War III-era Maneuver-Blade when Ulla seriously disables his machine. Ageha hacks the controls of the Bugmechs from the military and uses them against Ulla before Jimmy was able to broadcast real footage of the Hounds being shot to death by soldiers, turning the AGS security forces against the military before they could take over the Daiva Broadcasting building. In the course of events, Ulla is killed when Saiki guns him down. Haruki appears to the public in full health and takes over AGS and changes the name to Daiva Security as the president while Fumihiko retires to tend to the the sunflowers. Kariya and Jimmy have returned as DS employees. Saiki, on the other hand, disappears from Daiva City with no one knowing where he is.