Ken Mizoguchi

Ken Mizoguchi (溝口健,), or Gucchi (グッチー) as he was mostly called, was a Demille spaceship captain and Chuuta Kokonose's childhood friend.

Appearance
Gucchi is a young boy with red spiky hair (resembling that of Chuuta Kokonose's hair) and pair of red eyes.

As Demille spaceship captain, he wears red hooded jacket with white shirt or black turtle neck beneath, white pants, and grey boots. When he transferred to Chuuta's school, he wears the same white uniform as him.

Personality
Like Chuuta Kokonose, Gucchi is a kind boy who is loyal and cares a lot for his friends. He is cheerful around his close friends and likes to tease them, particularly Chuuta's habit of talking to himself prior of his knowledge about the Monitalien. He is also a good actor, able to convince other Demille members that he is on their side with his act that also surprises Chuuta.

History
Seven years ago, Gucchi used to play a lot with his three friends, Chuuta, Michiyo and Matsutarou. The four of them often gathered at Mount Taketori to play together. A month before the accident, Chuuta, Michiyo, and Matsutarou gave Gucchi parting gifts before Gucchi was supposed to move out, only to reveal after he received the gifts that the moving was cancelled because he had begged his parents not to since he would be lonely without the three of them. Because of this, following Chuuta's suggestion, the four of them decided to put the gifts inside the blue box from Michiyo and buried it as a time capsule that they promised to dig again together once they are older.

A month later, while playing near the cliff at Mount Taketori, the cliff collapsed. Gucchi, Matsutarou, and Michiyo tried their best to hang on as they asked Chuuta for help, but Chuuta accidently stepped on the rock that made them fall. Within the debris, the dying Gucchi was saved by Demille who then recruited him as part of them. For the past seven years, Gucchi decided to stick with Demille in hope to find Michiyo and Matsutarou, eventually becoming one of the captains of Demille's spaceships.

Season 2

 * Seven years ago, a month before the Mount Taketori incident, Chuuta, Michiyo, Matsutarou, and Gucchi gathered near a shrine to give going-away presents to Gucchi, who was about to move away; however, after his friends have given him their gifts, he revealed that he wasn't actually going to move away after all since his mom told his dad to cancel their plans since she thinks he'll be lonely without his friends; however, he still wants to keep their gifts despite the others wanting them back; when Chuuta suggested that they make a time capsule out of the gifts and put it in her box, he asked if he was talking to himself again, but Chuuta replied that this way the gifts will belong to everyone, including him; the others told him to put something in as well, and he decided to put in a photo of the four of them that his mom took; Michiyo and Matsutarou thought it was too little, but he protests that it can't be helped; the items were put into the box and they raced off to find a shovel to bury the box at the red torii
 * Appears in present day Chuuta's flashback of his friends falling from the cliff when Drew mentions his missing friends when talking about how much he's changed, since he's not running his past as much anymore
 * Appears in another flashback when Chuuta is thinking about how if he made the right decision, he could've saved his friends
 * In the present day, he transfers into Chuuta's class

Both Chuuta and Drew blatantly refuse, but Gucchi's subordinates, Sen and Sun reveal that they have captured Misuzu and Chips. Gucchi gives Chuuta a condition: If Chuuta willingly surrenders Drew to them, not only he will release the hostage, but he will also erase the memory about the accident seven years ago. Gucchi urges Chuuta to agree by reminding him how ever since that incident, Chuuta has been blaming himself and suffering because of it, but if the memory is erased, he doesn't need to suffer anymore. Chuuta refuses this offer, forcing Gucchi to proceed with threatening Misuzu's life. Noticing Misuzu's signal that she is awake, Chuuta uses Naminui to free her, giving her the opportunity to kill Sen and Sun and frees Chips. Misuzu immediately attacks Gucchi, but he easily deflects her attack. Using his SPH, D Blade, he smashes the ground which causes the debris to hit Misuzu, rendering her unconscious.

Before Gucchi can kill her with his bomb, Chuuta stops him by striking through his stomach with Naminui. With the recorder under his Demille tattoo destroyed and his two subordinates dead thanks to Misuzu, Gucchi reveals that he was only pretending to be antagonistic towards Chuuta and assures him that the people he had bombed before are still alive. He is actually very happy to have met Chuuta again and is relieved to know that Chuuta hasn't changed at all. He informs Chuuta that Michiyo and Matsutaro are still alive somewhere in space, so they should look for them with their respective group. Before leaving, Gucchi warns Chuuta not tell anyone about their conversation and not to worry about the cruel words his mother had said shortly after the accident.

Before going back to his ship, Gucchi secretly returns to his house and takes the blue box given by Michiyo with Chuuta and Matsutaro's presents inside, exchanging it for a photo of him with Chuuta, Michiyo, and Matsutaro along with his pin to give his mother message that he is still alive and to never blame Chuuta again for the accident.

Back at Demille spaceship, he orders for the ship to retreat since they already gained enough data. To himself, he thinks about how he is glad that Chuuta is in a good spaceship and eagerly anticipates the time they will meet once again.

Season 4
Gucchi's spaceship is shown to have crashed on a planet, with his crew dead and himself injured. He is standing in front of a group of people, the ones who caused the ship to crash. To prevent them from extracting any sort of information from him, Gucchi stabs himself, taking out his recorder in the process.

In his final moments, he sends a secret message to an unknown receiver and silently apologizes to Chuuta for not being able to reunite with him and their childhood friends. Then he blows himself up.

SPH
Gucchi's SPH consists of black blades and bombs that he materializes from his hands.
 * SPH Bomb - Gucchi uses a black round bomb to knock people unconscious and gives them the appearance of having passed away by covering them with black smoke from the explosion.
 * D Blade - Gucchi materializes black blades surrounded by red energies from his hands that have destructive power. The blades can also cut a simbiotic being from its host, without killing either of them, and gain the data from it.

Etymology

 * The name Ken means "healthy, strong" (健).
 * Ken's surname Mizoguchi means "groove, trench, ditch" (溝) (mizo) and "mouth, entrance" (口) (kuchi/guchi).

Trivia

 * The author, Akira Amano, originally planned to keep Ken alive.
 * Ken's hairstyle has a striking resemblance to that of Chuuta Kokonose's hair.