A PlayStation 2 port of the original game Soul Link Extension was released in Japan on June 29, 2006. It contains additional material to supplement the removal of adult content.
The series is also adapted into an anime series, and various manga and novels.
In AD 2045, a group of military cadets, attending the preparatory course of the Central Military Academy, proceeded for training aboard the space station Aries. Within this group of cadets were Ryota Aizawa and his classmates including Sayaka Nagase and Kazuhiko Nitta. The situation went sour when a terrorist group called "Jararacas" took over the station. While the military successfully evacuated the station, Ryota and his group were trapped aboard. Worse still, the boarding assault left most of the military forces dead, effectively leaving the cadets on their own.
An unexpected twist occurs when a mysterious virus was released within the station, gaining control of almost all personnel and turning them into mindless creatures in the process. This forced everyone, friend and foe alike, to find a way out of the station alive.
Ryota Aizawa (相澤 涼太 Aizawa Ryōta?)
- Voiced by: Hideki Ogihara
- A third year cadet with a timid and kind personality. Unlike his older brother, Shuhei, Ryota does not excel in a single subject, but is only slightly above average in most of his skills. One trait that is above others is his leadership skills, which is put to the test throughout the story. Though it is hard for him, he does not let his heart get in the way of his decisions.
- He is a childhood friend of Nao and later grows a crush on Sayaka.
- In the end of his third year, Ryota becomes the hero who saved Earth, and also gets elected as the student representative.
Sayaka Nagase (永瀬 沙佳 Nagase Sayaka?)
- Voiced by: Yuki Masuda
- Childhood friend of Ryota Aizawa.
Shuhei Aizawa (相澤 秀平 Aizawa Shūhei?)
- Voiced by: Kentarō Itō
- Ryota Aizawa's older brother. Shuhei is a brilliant and talented soldier who skipped two grades in the Academy. He is well renowned and surpasses most soldiers in combat.
- He is later revealed to possess perfect Sukyura cells, which enhances his healing capabilities. Although, unlike others who possess these cells, Shuhei does not turn into a mindless soldier. Cellaria was interested in him since he was able to fight off her control, and she intended to have him in order to create a superior being.
- In the end, though most of the world believe them to be dead since they supposedly died when the Aries station crashed into Earth, they — Shuhei, Nanami, and Nao — live happily together. They believed that people are not ready to acknowledge the existence of Sukyura. In the end of the series they were last seen in the airport near the place where Ryota and Sayaka are.
Nao Morisaki (森崎 七央 Morisaki Nao?)
- Voiced by: Kumi Sakuma
- Girlfriend of Shuhei Aizawa. A passionate and kind personality. She is a medical student in the Academy.
Kazuhiko Nitta (新田 和彦 Nitta Kazuhiko?)
- Voiced by: Takehito Koyasu
- A brilliant computer specialist and hacker. He builds a rivalry with both Aizawa brothers, though he does have a high respect for Shuhei.
Aki Nitta (新田 亜希 Nitta Aki?)
- Voiced by: Marina Ono
- Younger sister of Kazuhiko Nitta. An even better computer hacker. She does not have a stable relationship with her older brother, as the two would always argue when they see each other. Although, when they were younger, it seems that she used to look up to Kazuhiko until she realized that her brother was not serious in anything back then.
- In the end, she and her brother get along, and she once again looks up to him.
Yuu Yamanami (ユウ ヤマナミ Yuu Yamanami?)
- Voiced by: Junko Shimakata
- A passenger on the Aries Station. Quiet and mysterious. She was revealed to be a mercenary she seems to have a relation with shin when she was younger .
Cellaria Markelight (セラリア マーカライト Seraria Mākuraito?)
- Voiced by: Chiharu Tezuka
- Instructor on the Aries Station. Appears to be very caring towards her students. She is revealed to be the perpetrator and mastermind of the attack on the station. She ends up betraying the terrorists on the station and takes it over herself, with her Sukyura soldiers. She is considered to be the perfect Sukyura being and controls those who possess the Sukyura cells. She becomes intrigued with Shuhei since he is the only one that she cannot fully control. In the end, she is destroyed by Nanami.
Shigemichi Morimoto (森本 茂道 Morimoto Shigemichi?)
- Voiced by: Norio Wakamoto
- Steward of the Aries Station. He takes care of all passengers and acts as the general manager. A helpful personality. He is revealed to be Sayaka's father, who had left her when she was just a child. Unfortunately, he is killed before being able to tell her himself.
Gale Lantis (ゲイル ランティス Gairu Rantisu?)
- Voiced by: Takashi Nagasako
- Leader of the terrorist faction that boards the Aries Station. He dies buying time for Aya to escape.
Karen Tachibana (カレン タチバナ Karen Tachibana?)
- Voiced by: Yui Shōji
- A terrorist, and former soldier, that is skilled in hand-to-hand combat as well as firearms. An enthusiastic personality. She may seem insubordinate, but she respects Gale, and sees him as a father figure. She grows a liking for Kazuhiko and in the end, she is seen in a dress meeting up with him.
Aya Sugimoto (杉本 亜弥 Sugimoto Aya?)
- Voiced by: Yoshino Nanjō
- Childhood friend of Sayaka Nagase. A clumsy, but kind personality. Ever cheerful at all times.
Nanami Inatsuki (稲月 ななみ Inatsuki Nanami?)
- Voiced by: Natsumi Yanase
- A strange and young girl found on the Aries Station. She is later found out to be a creation of Sukyura cells and human cells; basically a result of when Shuhei and Nao consummated their relationship (In a way, she is their "child"). She calls Shuhei, her 'father', and Nao, her 'mother'. In the end, she became the one that destroyed Cellaria, as she was the only who can counter Cellaria's ability to spread Sukyura cells.
Soul Link is presented on a range of media types, ranging from the game itself, the anime, two light novels and several drama CDs.
A 12-episode anime adaptation was made.
Three Soul Link novel adaptations have been released. Two are published by Soft Garage and one is an anthology collection published by Jive.
An anthology collection referred to as Twin Heart Comics Soul Link consists of manga relating to Soul Link by various artists and a manga adaptation titled Soul Link Signal Code: 0 was released on April 4, 2006.