Idagawa Ren

About
"Idagawa Ren, upon hearing Zanma Rouga's plan to conquer Japan"

- The one to conquer the country... will be me, Idagawa Ren.

Idagawa Ren is the banchou of 750 Academy, as well as the leader of Gokuren, a large biker gang. He plans to conquer Japan.

Prior to the events of Big Bang Age, 750 Academy is part of Sensouji Academy, a subdivision of the PGG, one of the major powers in Japan. Ren and his biker gang despise Sensouji and the PGG and wish to beat them and conquer the nation. Ren then runs into Kamui, who gives him a Sacred Student Button, granting him tremendous power.

During the events of Big Bang Age, Zanma Rouga defeats Yamizaki Akito, the banchou of Seijou Academy, located in the Sensouji-controlled Toukyou ward. Rouga then establishes Wolf Fang and continues his plans of conquering Japan. Ren uses the opportunity to rebel against Sensouji and start his own plans to conquer the nation.

Ren soon hears that Wolf Fang is housing a woman who is wanted by the NPI, another major power of Japan and a major adversary of the PGG. Ren starts fighting against Wolf Fang and instructs Senpuuji Kyouko via a letter to try and capture the woman, planning to garner favor with the NPI and gain their help fighting the PGG. However, unbeknownst to Ren, Kyouko does not carry out his orders.

After fighting against Wolf Fang for a while, Ren leads a raid attack against Wolf Fang directly at their headquarters, but he's ultimately defeated and forced to retreat back to 750 Academy for a while.

If Wolf Fang chooses to defeat Sensouji first, Ren plans another raid attack in the middle of the night. Here, he runs into Kamui again who states he wishes to have the Sacred Student Button back to give it to a "more fitting person". Ren declares that he needs the power so Gokuren can conquer the nation and draws his weapon. Kamui ultimately kills Ren and presents his corpse to Rouga.

If Wolf Fang chooses to defeat Gokuren first, Ren attempts a last ditch raid attack on Toukyou after losing his headquarters to Wolf Fang. Rouga defeats Ren and holds him in prison. If Senpuuji Kyouko has joined Wolf Fang she will secretly visit Ren in prison. She's there to talk to Ren about the death of Hokuto, Kyouko's husband and Ren's best friend, three years prior. Kyouko holds Ren responsible for his death and wishes to avenge her husband by killing him. Ren, who has secretly been beating himself up over Hokuto's death but does not admit it, allows himself to get killed by Kyouko.

If Kyouko is not part of Wolf Fang then Rouga can convince Ren to join Wolf Fang.

Trivia

 * Ren is the only antagonist in the game who can directly attack Wolf Fang headquarters even if he does not control a region that's adjacent to it.
 * Ren's motorcycle, a Z750 F-D, is a reference to a series of motorcycles produced by Kawasaki Heavy Industries, specifically the Z750 line of motorcycles which date back to the 1970's.