- Kane Blueriver (カイン・ブルーリバー Kain Burūribaa?)
Voiced by: Souichiro Hoshi (Japanese), Steve Metz (English)
- Kane is the protagonist of the adventure. He is an intergalactic trouble-Contractor. He is a tough and reckless adventurer who captains Sword-Breaker, the legendary lost space ship from an ancient civilization. He acquired his spaceship from his grandmother and constantly recites quotes of her. A free spirit, keeps an open mind whatever the situation. Ever the optimist, he is always confident he will prevail over whatever troubles await him. His motto is "carry out any difficult assignment to the end!" Kain is the master of the Psi-Blade, a weapon of psi energy, requiring tremendous mental strength.
- He always wears a black cloak, apparently also worn by his grandmother.
- Canal Vorfeed (キャナル・ヴォルフィード Kyanaru Vorufiido?)
Voiced by: Megumi Hayashibara (Japanese), Jessica Schwartz (English)
- Canal is a female human-like hologram. She is the computer terminal of the Sword-Breaker. She has a distinctive personality, emotions and reasoning abilities. Her usual form is a teenage girl, but if necessary, and she can morph her form into a baby, a noble lady or other objects, whatever is needed to help Kain in his missions. Her motto is "carry out any difficult assignment to the end, as long as it shows a profit!" Canal's mind functions as a computer...she is very practical, analytical and logical. On the other hand, she sometimes shows her emotions when she teases Kain for his mistakes or has a quarrel with Millie Farrier.
- She is a bit selfish, doing a lot of negative actions for the Sword Breaker owner (Kane Blueriver), like turning off Life System only for getting a job Kane didn't want
- Millennium "Millie" Feria Nocturne (ミレニアム・フェリア・ノクターン Mireniamu Feria Nokutaan?)
- "Millie" is an uninvited assistant to Kain. Jealous of Canal, Millie is a happy-go-lucky girl who is a self-professed, but amateur private detective. She has very basic detecting' skills like opening a locked door with her hair pin! Her dream is to be the best in the universe' at everything she does. At work, she is indeed the best shot in the universe...but at home on Sword-Breaker, is another matter. Providing a bit of comedy, she routinely blows up the kitchen, but somehow the meals turn out delicious.
- She meets Kane and Canal in the first episode but doesn't actually join them until the second. She travels with them throughout the series.
- Raily Claymore
- A handsome and smart police inspector of Interstellar Police. Kain has a sort of inescapable "give-and-take" relationship with this young inspector. He often contacts the crew of the Swordbreaker with mission requests, that are not always requests.
- Nina Mercury
- The secretary of Raily Claymore. Nina is so deeply in love with Raily that she is fascinated by his gaze and forgets what she is doing. Two running gags in the series focus on her actidentally spilling coffee on Rail, and shortening out any machine with the slightest touch. The latter is actually useful in several adventures.
- The master of giant company called Gazer Konzern and the boss of mega-crime organization; Nightmare. He is the master of the Lost Ship Darkstar and intends to control the whole universe. Stargazer possesses a power to destroy the mind of a person from afar.
- Spreader of Darkness
- A young-looking guy who works for Stargazer, and master of Goln-Nova, one of the legendary Lost Ships. He commands Glen and Carly at Nightmare. He was injured in the battle with Alice 10 years ago pre series and has since been in statis. He woke up after sleeping for 87016 hours in a capsule.
- An assassin of Nightmare who admires Spreader of Darkness and wants him to acknowledge her strength. Carly's hobby is hunting and her favorite prey is Kane. She is good at many types of weapons but prefers an energy whip.
- Director of 2nd business department of Gazer Konzern and the assassin of Nightmare. Glen tries to kill Kain with various tactics.
- A female child made for a meta-psychology experiment that Kane and Mille rescued. She can control all meta-psychology-related instruments with her mind, and all of them become useless when she's scared. Her nickname is Anis.
- She only appears in the manga.