Samanosuke was created based on the likeness of Japanese actor Takeshi Kaneshiro and with a background loosely based on Hidemitsu Samanosuke Akechi, later known as Tenkai Nankobo. Being the main character in Onimusha: Warlords, Onimusha: Blade Warriors and Onimusha 3: Demon Siege. After his defeat of Nobunaga he is no longer the lead character but is still an important character in later games as he heavily aids Soki and the others in stopping Fortinbras. Although most of Japan's medieval history has been played out, the ending is slightly ambiguous with Samanosuke still needing to seal away the gauntlet's powers for good.
Samanosuke was born in the year 1535, during Japan's Sengoku Period. The circumstances of his birth (location, exact date) are unknown, but it is implied in Onimusha: Warlords that Samanosuke was a samurai in service to the Saito clan of Mino province (now Gifu Prefecture). A struggle for leadership in the clan (the first game references the historical in-fighting between Dosan Saito and his son Saito Yoshitatsu) previous to the events of Onimusha: Warlords saw Samanosuke separate himself from the clan and travel the world, effectively becoming a ronin. During these travels he encountered and befriended the female ninja Kaede, who became his partner and confidant.
Over the next 4 years they both develop trust, honor, respect and deep feelings for each other (as seen in Onimusha Blade Warriors). Upon his return somewhere in 1573 (months after the events in Onimusha 2) Samanosuke and Kaede return to assist his uncle, Mitsuhide Akechi, in an absolute secrecy. For the next 11 years Samanosuke and Kaede travel all over Japan, slaying Genma wherever they may find them.
Samanosuke is first seen in the game's opening cinema on a cliff overlooking the Battle of Okehazama in 1560. In a reference to the Nobunaga's Ambition series of video games, the battle ends with Nobunaga Oda being fatally shot through the throat on the eve of his victory. The opening cut scenes of the game go on to illustrate that it’s one year later and that Samanosuke has returned to Japan to honor the request of Princess Yuki, daughter of Dosan Saito. In her letter to him she expresses fear at the strange events taking place in her home, Gifu Castle, and pleads for Samanosuke to "save her". He responds, but is too late to stop two demon ninja from abducting her. The opening cinema closes on a shot of an apparently live and well Nobunaga seated atop a fierce warhorse at the head of a massive army.
Samanosuke catches up with the ninja on the outskirts of the castle and fends them off, but his reunion with Princess Yuki is brief as Osric, a giant red demon wielding a massive club, springs from the ground. The battle between the two is short-lived, and Yuki is taken away by the demon as Samanosuke loses consciousness, while unconscious, Samanosuke is met in a void by the spirits of the Oni clan (this was translated as "Ogre" in the first game, and subsequently as "Oni" for the rest of the series). They give him their power in the form of a magical gauntlet, which allows Samanosuke to absorb the souls of fallen demons and equip various weapons charged with elemental energy, tasking him to defeat the demons.
As Samanosuke adventures through the castle and the surrounding areas, he uncovers a plot by Nobunaga's general Tokichirou Kinoshita (the game asserts that this man becomes Hideyoshi Toyotomi later in life) and the demon scientist Guildenstern to use Yuki as a sacrifice for a dark ritual to give the resurrected Nobunaga untold power. As Guildernstern's notes explain, the Genma (the name of the demons in the Onimusha universe) have made this contract with other humans in the past (examples cited by Guildenstern include Alexander the Great and Genghis Khan); in exchange for loyalty to the genma and a guarantee of constant human sacrifice, the genma give the contractee their power and superior technology.
To perform the dark ritual, the genma require the blood of a pure woman who was born in the land the contractee is from, held within a chalice made from her skull, which is to be blessed by the genma king Fortinbras and drunk by the contractee to seal the deal. Through his efforts in the game, Samanosuke manages to thwart the plans of the genma, transform into a True Onimusha, and kill Fortinbras at the game's climax. Shortly after his defeat of Fortinbras, Nobunaga is seen glaringly looking down at Samanosuke from above. The epilogue of the game explains that Samanosuke's whereabouts are unknown. The player can assume that Samanosuke survived, however, as a cut scene after the credits show him looking upon Inabayama Castle from a distance.
Onimusha 2: Samurai's Destiny
"Then a young warrior, Samanosuke Akechi stood up and defeated the demon king." --Narrator
While Samanosuke does not appear in Onimusha 2, he is mention in the story intro and the effects of the first game are registered in several documents found by Jubei Yagyū. He is mentioned by name in one particular document labeling both him and Jubei as high-level threats.
Onimusha: Blade Warriors
"Kaede... it is you that givens me the strength to fight. It has always been so and always will." --Samanosuke to Kaede
It is later explained by Samanosuke that he was able to escape and says that he hid himself away from everyone. After Samanosuke destroyed Fortinbras he couldn't remember what had happen to him when he woke up and saw Nobunaga looking down at him. He saw that Fortinbras had been killed but not by human hands. He then feared that if he was in his full Oni form again that he wouldn't be able to control himself if he started hurting the people he loved, mainly Kaede. Samanosuke went away for 10 years until Kaede found him.
Samanosuke discovered that Marcellus was once an Oni-Warrior during the Oni-Genma Wars and killed in the battle resulted by treachery, that Guildenstern took Marcellus's dead body and modified him into what he is. Samanosuke feared that if he didn't find a way to understand the Oni powers inside of him then he could have become what Marcellus was. During those years he was away, Samanosuke was able to understand and fully mastered the mystic powers of his Oni gauntlet.
During the events of Blade Warriors, Samanosuke and Kaede team up with Jubei and his teammates from Onimusha 2.
Onimusha 3: Demon Siege
After Onimusha 2, Nobunaga is defeated by Jubei Yagyu but is not destroyed as Jubei was not powerful enough and didn't have an Oni gauntlet to take Nobunaga's soul. He is revived again in 1582 as the King of the Genma and begins anew his conquest of Japan. Akechi Mitsuhide, Samanosuke's uncle, rebels against his former master and launches an attack at Nobunaga, who is at Honno-ji Temple (this mirrors his Incident at Honnō-ji though the events depicted in the game are altered to conform with the series storyline). Nobunaga sends for reinforcements in the form of a Genma tank (depicted as a giant creature resembling an insect) and surrounding forces. In the opening cinematic of the game, Samanosuke (dressed as a ninja) intercepts these reinforcements and ultimately destroys them, including their commander Gargant in a duel. He then sets off to join Mitsuhide in the final assault.
Samanosuke takes part in the siege on Honno-ji Temple and corners Nobunaga and his retainer Ranmaru Mori in the flaming temple (around this time Jubei had gone into hiding, to avoid being hunted down by genma minions of Nobunaga). He defeats Ranmaru without much effort, and then Samanosuke and Nobunaga duel for a short period in which it becomes clear that Nobunaga is superior. Before the Genma Lord can deliver the final blow, Samanosuke and the body of Ranmaru are sucked into a strange vortex and disappear.
Samanosuke reappears in Paris in the year 2004 and briefly encounters Jacques Blanc before Jacques is sucked into a similar vortex and also disappears. Through a meeting with the genma scientist Guildenstern, Samanosuke learns the year in which he has arrived and also learns that the genma have been experimenting with time travel, a process by which they can travel to any point in history. He also finds that his gauntlet has lost its Oni Power.
Meanwhile in the year 1582, seven days before Mitsuhide's assault on Honno-ji Temple, Jacques Blanc appears near Mount Hiei. He is given a similar magical gauntlet to Samanosuke's by an Oni spirit who tells him the only way back to his original time is to aid Samanosuke in defeating the genma. The Oni spirit also gives Jacques a partner, a small raven-winged being identified as a tengu named Ako, through whose power Jacques can communicate with others around him and with Samanosuke in the future. He then encounters an alternated Samanosuke of a different timeline, and promises to help him.
Samanosuke and Jacques battle against the genma in their respective times, at certain points aiding each other indirectly and building their Oni Power. During this, the Samanosuke in Paris encounters a revived (and mutated) Ranmaru Mori, and is forced to battle him on several occasions, the final of which takes place atop the Eiffel Tower where the genma have installed the time fold generator. Although he defeats him, Ranmaru still manages to activate the generator before passing out, much to Samanosuke's despair. In the past, Jacques Blanc and Samanosuke reach Honno-ji Temple to battle Nobunaga. Nobunaga defeats (but does not kill) the alternated Samanosuke easily and then squares off against Jacques. In a duel Jacques defeats the Genma Lord, seeming to have vanquished him, and helps Samanosuke to his feet.
He then starts to glow white, signalling that he is now able to return to his timeline. Jacques says goodbye to Samanosuke and proceeds to be consumed by the vortex of the time fold, only to watch helplessly as Nobunaga recovers and kills the alternated Samanosuke.
Before returning to his timeline in a similar fashion, Samanosuke bids farewell to Jacques, Michelle and Henri. Arriving to Honno-ji Temple, he absorbs the power of the fallen alternated Samanosuke and transforms into his Ultimate Onimusha form, looking similar to, but much more powerful than, his True Onimusha form in the climactic final cinematic of Onimusha: Warlords against Fortinbras. In the final battle, Samanosuke destroys Nobunaga and absorbs his soul into the gauntlet, preventing him from returning again.
In the epilogue, the narrator tells us that Samanosuke has embarked on a new quest: to seal the gauntlet containing the soul of the Genma Lord. The end-credits cinematic of the game shows Hideyoshi Toyotomi (known as Hideyoshi Hashiba at the time), who appeared in both Onimusha: Warlords and Onimusha 2 at the head of an army, saying it is now his time to rule as his eyes glow eerily red.
Onimusha: Dawn of Dreams
A mysterious monk named Tenkai Nankōbō now resides at the ruins of the temple on Mt. Hiei. Tenkai wears red armor, a large jade necklace, and on occasion a red mask, for which he is also referred to as the 'Red Demon'. He has grey hair but seems youthful despite admitting that he has lived so long he has forgotten his age. Tenkai's companion is Arin, a girl with mysterious powers with a nun-like quality.
Sensing an air of evil starting to spread across the land, he eventually discovers Hideyoshi Toyotomi's bold and insidious scheme, and sets out on a journey to find the person that possesses the power of the Oni to help him bring Hideyoshi down. This turns out to be a young man calling himself Sōki, who actually turns out to be Hideyasu Yūki, Hideyoshi's illegitimate son. As Tenkai joins Sōki's party to fight the Genma, Arin stays behind at Mt. Hiei.
During the game's end credits it is revealed that Tenkai is none other than Samanosuke, and Arin is actually Ako. The last we hear from Samanosuke is that he is off on another journey, this time, to seal the Oni Gauntlet, once and for all.
"So... fortune has smiled upon me this day... with the power of the gauntlet, I will destroy all of those monsters and save the princess."
The Gauntlet that was given to Samanosuke Akechi was created by the power of the council of the twelve Oni Gods. It absorbs the souls of the Genma, gives power to Samanosuke's weapons and changes the color of the orb in its center to match with that of the corresponding weapon, allows him to achieve an Oni Awakening, and is capable of functioning with other Oni items such as the Oni Army Orb.
The Gauntlet grants Samansouke immortality and allows him to instantly change from one Oni weapon to another.
Samanosuke usually wielded a sword; the only exception being the Chigo, which was an axe. Each one had their own advantages and elemental power.
- Normal Sword - A samurai katana, an heirloom apparently passed down through Samanosuke's family. Without magic power and minus the ability to charge attacks, this weapon holds little power against powerful supernatural monsters of the Genma army.
- Raizan - The blue legendary sword of lightning, acquired in Warlords, is rather normal in shape compared to the others. Raizan's magic enables it to unleash close range bursts of lightning energy on a single opponent with each strike.
- Enryuu - This red flaming broadsword, found in Warlords, is a heavy weapon, and it swings a bit slower than the others. Its magic attacks allows Samanosuke to project a forward blast of fire that strikes all opponents in front of him.
- Shippuu - This green naginata-style weapon, acquired in Warlords, is a dual-bladed spinning weapon. Its magic attack enables Samanosuke to generate a whirlwind around himself by spinning it over his head, enabling him to strike multiple enemies in a full 360 degree range.
- Bishamon Sword - The ultimate sword bearing the name of the God of War. It has extraordinarily high damage that can kill nearly any Genma in one strike. It has a special 360 degrees slash which is far more powerful than the normal strike and eliminates most enemies in one hit, even from full health.