Sekigahara

The Battle of Sekigahara (関ケ原の戦い, Sekigahara no Tatakai) is largely considered to be one of the most decisive battles in the late Warring States period. Essentially, it is a power struggle for the right to rule the land after Hideyoshi's death. The Western Army was plagued by disunited forces, and many key positions and allies deserted or defected during the battle, resulting in a decisive defeat.

Other battles considered a part of this campaign are the siege at Fushimi Castle, the second siege at Ueda Castle, the Uesugi-Date conflict at Hasedō, the clash at Ōtsu Castle, and the Kyushu campaign at Ishigakibaru. The armies led by the main commanders first clashed at Kusegawa, but this battle decided the fate of both armies.

Samurai Warriors
There are many possible outcomes to this battle in Samurai Warriors 2, but there are also certain events that remain consistent in most scenarios. Near the start of the battle, each army desires to protect their cannons while claiming the opposing army's artillery for their own. Ieyasu will order Magobei Fuse to fire at Mount Matsuo, in which Hideaki Kobayakawa remains indecisive in a garrison. If the ploy fails, he will send Hanzō to threaten the man. If the Eastern Army succeeds in any of these schemes, Kobayakawa will defect and the morale for the Western side will decrease dramatically. Players are additionally given the option to allow or prevent Hidemoto Mōri and Hiroie Kikkawa switching allegiances by dealing with Ekei Ankokuji. Ginchiyo will also choose to charge the Eastern camp from the north, which may hamper the Eastern army's progress.

Officers for the East may also choose to protect Naomasa Ii and Masanori Fukushima as they perform an overzealous charge against Mitsunari; losing them will lower ally morale. Yoshihiro will decide to retreat and pave his way through the Eastern Army if the Western Army begins to crumble. He will instantly route any NPC officer that he runs into, warning them on each instance to get out of his way. Defeating him is optional and he will die if the player chooses to do so. The East claims victory on Mitsunari's death and expand the Tokugawa's influence, eventually leading to the Siege of Ōsaka.

Generally, the Western Army officers will be given the chance to route Ieyasu's forces by countering the Eastern Army's strategies. Ina will await in the upper-left garrison and charge downwards for the Western camp after some time passes. If the Eastern Army fares badly, Tadakatsu will ride to the center of the battlefield to raise the morale of his comrades. During this time, every Eastern officer will be in hyper mode and Mitsunari orders the player to stop Tadakatsu. Following his defeat, they can also pursue him at Edo Castle. There is also the instance where Ieyasu also dies upon his defeat such as in Motochika's story mode.

Musashi begins his story here as a warrior on the fallen Western side and has to fight for his survival. During the fighting, Kojirō Sasaki will assassinate Tamehiro Hiratsuka and Hirotaka Terasawa.

Major differences can also occur in certain characters' dream stages such as Yukimura, Nene, Masamune, Hideyoshi, Motochika, and Yoshihiro's.

Sekigahara also acts as the final showdown for Kenshin and Shingen in their respective storylines: On Kenshin's story, Shingen managed to gain the loyalty of the Tokugawa and they will arrive to assist the Takeda, however the Uesugi gained reinforcements of their own and defeated the Takeda; On Shingen's story, while battling Kenshin, Oda officers arrived as a third party under the flag of the Azai and the Asakura, and when Yoshikage retreated, Oda and Azai officers joined Kenshin's forces, while the Tokugawa led by Tadakatsu also joins the Uesugi. Sekigahara is also the location for Nagamasa's dream stage: After assisting the Oda in Kanegasaki, Nagamasa became Nobunaga's most trusted ally and helped Nobunaga defeat a 3 army coalition of the Takeda, Date and the Uesugi.

In Samurai Warriors 3, the battlefield is shrouded in a fog of war. Masanori and Naomasa will arrogantly try to charge for Mitsunari while Sakon rains cannon fire on the battlefield. To get Hideaki to join, the player must succeed in all green-colored objectives for the following characters. Mitsunari, Sakon, and Muneshige gets the Western side as part of their story, while Ieyasu, Tadakatsu, and Mitsuhide gets the Eastern side. Yoshihiro also gets the Western side as part of his story, except that his version is exclusive to him. Instead of defeating Ieyasu, Yoshihiro must escape to the Southwestern Garrison with Muneshige.
 * 1) For Mitsunari, Ieyasu, Masanori, and Gracia's story, Hideaki's defection is scripted and cannot be avoided.
 * 2) For Tadakatsu's story, the player must defeat 200 enemies, prevent Yoshitsugu Ōtani from reaching Masanori, stop Hiroie Kikkawa and Hidemoto Mori's advance on Ieyasu, then finally defeat Sakon Shima and Yukinaga Konishi within 2 minutes.
 * 3) For Mitsuhide's story, Hideaki will refuse to defect and may even attack Ieyasu once the opportunity presents itself.
 * 4) For Sakon and Muneshige's story, Hideaki will remain loyal if the player stops Kanbei from meeting with him.
 * 5) For Okuni's story in the expansion, the conditions for Hideaki's defection include defeating 100 enemies to clear away the fog, prevent Kikkawa and Mori's advance on Ieyasu, protecting Masanori from Ginchiyo and Mineshige, and defeating Sakon in 3 minutes.

In the expansion, Okuni and Masanori gets the Eastern side as part of their story. Gracia also gets Sekigahara as part of her story, except that it is hypothetical, as Mitsuhide's army clash with both the Western Army and the Eastern Army to control the land. Motonari is also present for Okuni's story, while Kiyomasa is present for Masanori's.

On Naomasa's tale in Samurai Warriors 4-II, Yoshitsugu suddenly detects Ieyasu's attempt to make Hideaki defect and has him executed before ordering Hidemoto Mōri and Hiroie Kikkawa to attack the Eastern Army. Similarly, in the Trials of Trust campaign, Nobuyuki and Ina arrive with late reinforcements with Ieyasu reporting that Hideaki, the Mōri and the Kikkawa have all refused to defect, and are now threatening the Eastern Army's main camp. Takatora's tale has him already take into account Hideaki's betrayal, but only the Kikkawa remain with the Western army, Yoshitsugu will also be promoted to the Western Army's commander once Mitsunari leaves the battlefield. In Sakon's scenario, the battle plays out closely from the original Western Army's side of the battle, but instead of fleeing to the escape point, the objective changes to launch an attack at Ieyasu after helping the other officers evacuate. In Yoshitsugu's scenario, Hideaki's false loyalties are already known, and Yoshitsugu positions himself closer to Hideaki. Once Hideaki defects, Yoshitsugu will immediately intercept the betrayer along with Takatora who suspected a possible intervention in the scheme. After the Kobayakawa unit's defeat, Yoshitsugu immediately moves to rescue the Kikkawa and the Mori to keep them from defecting as well.

Warriors Orochi
During Wu's story in Warriors Orochi, Sun Ce has just failed to rescue his father from Orochi. Called a traitor by his siblings, he confronts them here to work out their differences. Sun Ce's army starts in the center of the field, surrounded by cannons and four generals. Ina, as Sun Shang Xiang's friend, appears to test Sun Ce's resolve twice. Convinced that the older brother is truly thinking of his family, Ina decides to believe in his integrity. After some time passes, Sun Shang Xiang and Da Qiao appear to fight the ally forces. Sun Quan and Zhou Tai will also enter the fray after some time passes. After the battle, Sun Shang Xiang and Ina joins Sun Ce's forces.

In Warriors Orochi 2, it will serve as the final stage for the Samurai story mode. Sakon will lead the united Shingen, Kenshin and Nobunaga forces to defeat the resurrected Orochi. A mist surrounds the battlefield and clouds the players vision of the map in the pause menu. With Sakon's forces crowded in the center, Masamune orders his troops to unleash their cannons. With barrage ensuing, Keiji springs an ambush on Shingen, who guards the main camp. Da Ji causes an illusion of falling rocks to disturb the army at Mount Matsuo, which Fu Xi volunteers to dispel. As the cannons and the aforementioned threats are dealt with, Sakon's army gains a significant morale boost. Da Ji tries to summon phantom soldiers to thwart the coalition's advance and a nearby Fu Xi will manipulate them for his own use. Defeating the vixen disperses the fog over the field and triggers the last push the army needs to charge. Completing this stage will unlock Kiyomori Taira.

Musou OROCHI Z offers a new dream mode stage with Yoshitsune, Benkei, and Kiyomori forming a Genpei era team against the heroes of the other time eras. Their allies are other notable figures from the Three Kingdoms era, such as Liu Biao, Gongsun Zan and others. With He Jin acting as the main ally leader, the Genpei team need to defend him while they defeat their other rivals. Many of the ally generals are not pleased to be teamed up with the player's party. Dong Zhuo falters against the Uesugi army's charge, Yuan Shao avoids Kiyomori's advice and is ambushed by Shingen, and Meng Huo and Zhang Jiao are "fished in" by Yoshihiro and Ieyasu's trap. Defeating the enemy generals that trap ally generals rectifies their weariness and restores morale. Nobunaga then orders Masamune and Yoshimoto's cannons to fire. Stopping all three cannon positions opens the gates to Nobunaga's fort. After the battle concludes, Yoshitsune renounces his temporary alliance with Kiyomori and leaves with Benkei.

In Warriors Orochi 3, Hanbei and company head here to rescue Da Ji from Nezha and the Mystic army. Players must come to Da Ji's aid as soon as possible or the battle will prematurely end in defeat. Lu Bu will momentarily arrive to distract Nezha before being warded off by the latter.

In Ultimate, Nezha, Susano'o and Shennong reimagine the chase in the area had Susano'o accepted Shennong's treatment after being wounded by the Hydra. Once the chase begins, Nezha encounters Achilles who will move to slow the advancing Mystic army. When Achilles is defeated, Himiko arrives with Kai and some members of the coalition as reinforcements for Da Ji, but Mystic reinforcements also arrive to help Susano'o. Once Himiko and the rest of her reinforcements are defeated, Motonari will lead the Mystic troops into an ambush to stall for more time. During the battle, Lu Bu appears suddenly to challenge Nezha and must be defeated to continue the chase. Once the Mystic army finally catches up to Da Ji, Hanbei and Kaguya appear to try to talk Susano'o into stopping hostilities but are attacked as well. Still, the interval brought by Kaguya still allows Da Ji to escape, and Shennong leaves Susano'o to help the humans instead.

In Warriors Orochi 4, Nene, Lu Meng and Zhang Chunhua came to stop the quarrel between Mitsunari and Ieyasu which referred as Western Army and Eastern Army. However the Wei forces came to aid the Toyotomi army while Shu forces came to aid the Tokugawa. The Wei-Toyotomi and Shu-Tokugawa collides each other. After they are defeated, they became their allies.

Kessen
In Kessen, this battle will decide who lives or dies for the remainder of the game's campaigns. The concepts of the Western and Eastern army remain after the battle's conclusion. In the Tokugawa camp, the pre-battle cutscene dramatizes the former Toyotomi general's reasons for joining Ieyasu. Moments before the battle commences, Ieyasu sees a vision of Nobunaga bidding him to continue his legacy. Determined to win, Ieyasu draws out his sword and, whilst declaring his desire to rule, cleaves the mist enshrouding the battlefield. Scoring a victory in this battle acts as the first step for Ieyasu's path as shogun.

By contrast, the Western Army scenario touches on some of the generals' conflicting feelings regarding Mitsunari. Undeterred by news of betrayal amongst their ranks, Mitsunari marches into battle. He swears to protect the Toyotomi family and repay his debt to the late Hideyoshi. If Mitsunari wins this battle, he will pursue the fleeing Ieyasu with reinforcements from the Sanada troops. Losing any major battle after this will usually result in Mitsunari, Sakon, or Ōtani's deaths. Winning every battle for the Toyotomi side will secure their family's reign by Mitsunari's hand.

Depending on the actions of the player, the armies will fight at Sekigahara again as their final battle.

The area serves as a battle ground twice in Kessen III. While escorting his sister to her future husband, Nobunaga has to simultaneously protect her from his rivals. He returns here once more after the incident at Honnoji to "revive" his name to the public eye and surprise the Akechi troops.

Harukanaru Toki no Naka de
The backstory for Harukanaru Toki no Naka de 5 mentions the battle as the driving cause for the Four Gods' corruption and separation from one another.

Saihai no Yukue
Sekigahara is the main setting for Saihai no Yukue. The player sees the game from Mitsunari's point of view which antagonizes Ieyasu. The story explores characters and famous events before the main confrontation. Though Mitsunari is routed by Ieyasu, he escapes capture and reappears with three generals. With two additional generals as reinforcements, he turns the tide of the battle and ends the conflict by sunset the same day.