Toshinden 4 (闘神伝 昴, Toshinden Subaru in Japan) is the fourth installment of the Battle Arena Toshinden series. Unlike previous installments, it only saw release in Japan and the PAL region. It was released a total of three times in Europe; it originally came out on June 30, 2000, and was re-released on The White Label Range on April 12, 2001, and was re-released again by Play It On, November 20, 2003.
Ten years after the events of Battle Arena Toshinden 3, Eiji Shinjo, who is now the new leader of an organization called the "Gerard Foundation", has organized a fourth Toshinden tournament which revolves around the gathering of four holy weapons that can be used to either save the world or destroy it. Eiji's old enemy, Vermilion, is after the four holy weapons for his own malevolent ambition and that many fighters from within the tournament, including Eiji's own nephew Subaru, will find themselves getting caught from within the conflict itself. Can Eiji stop Vermilion before it's too late?
A plot point introduced in this game focused on the Four Sacred Arms. Though seen in full since Battle Arena Toshinden 2, their relevance was never previously brought up. Each weapon bears a reference to one of the Chinese cardinal beasts, Byakko, Suzaku, Seiryu and Genbu. The weapons also seem to change appearance depending on the user. While the Byakko no Tachi (White Tiger Fang) is usually seen as a rather plain katana, the Seiryu no Yari (Azure Dragon Spear) was a long leaf tipped spear while held by Mondo, yet altered to an ornate golden rod in the hands of Eos. As a purely cosmetic addition, when using a certain attack, an image of the beast associated with the weapon will display in the background.
Plotwise, it was said that when all four weapons were gathered together, they would bestow tremendous power on a person. Most characters in the game have their endings based around uniting the weapons and receiving the power of them. In some endings, they use this power to speak to a parent or loved one. However, Eiji's ending reveals the true nature of the power behind the weapons: It is the "Toshin", or god of fighting. This being is definitely not the one worshipped by the Organization of Toshinden 3, Agon Teos, since Vermilion makes a clear distinction between the two in his own ending.
- Subaru Shinjo - The main protagonist of the game. The son of Sho Shinjo and Cupido, Subaru is a traveling swordsman who seeks to locate the whereabouts of his missing uncle, Eiji.
- Naru Amoh - The main deuteragonist of the game and Kayin Amoh's foster daughter who was last seen as a playable character in Toshinden 3 (albeit when she was a small child). Now that she's a teenager, Naru joins forces with Subaru and Rook in order to participate in the tournament, hoping that she'll be able to figure out on what had happened to her foster father, who had disappeared after the events of Toshinden 3.
- Rook Castle - A nunchaku-wielding American youth who dreams to meet and test his own fighting skills against his idol, Eiji Shinjo from within the tournament. Aside from that, he also wants to find a mysterious ninja girl who had defeated him in a street fight from within the past.
- Puella Marionette - A young petite Swiss girl who fights to defend the world's peace while wielding the Suzaku Bow (the same weapon that Uranus had used from within Toshinden 2). It is strongly implied from within her backstory that Uranus was her late mother.
- Lancelot Lakeknight - A noble yet cowardly English fencer who seeks to improve himself after a past battle against Naru.
- Fen Barefoot - A young Brazilian boy/fisherman who seeks revenge against Genma for the death of his grandfather. He has a pet pig named Wolfy who accompanies him wherever he goes and that Wolfy is able to attack if given a command from Fen.
- Genma - A mysterious yet malevolent Chinese magician who seeks to gain the four holy weapons for his own personal greed. He is extremely old, more than 2,000 years old.
- Miyabi - A young Japanese kunoichi who was kidnapped by Genma and brainwashed into becoming his personal servant.
- Bang-Boo - A Cuban cyborg who has been programmed to work for Genma and Miyabi.
Team 4 (unlockable characters):
- Eiji Shinjo
- Eos - An Italian angel-esque altered human who works with Eiji from within the Gerard Foundation. She keeps her eyes closed and rarely opens them.
- Zero - A Greek synthetic human who also works with Eiji from within the Gerard Foundation.
Team 5 (unlockable character):