Unskilled, but Strong: For the most part he just uses Linebarrel's extreme power to win. Although he can hardly be called a poor fighter, compared to Reiji's skillful swordsman ship he basically just wacks people with his swords as hard as he can and can't really use the Executor as anything other than a wide area single shot blast. He pretty much could not beat Reiji straight up, without using modes B and C to overpower him. In the manga he's shown to be a flat out terrible pilot if he can't use Linebarrel. In one fight he needs to use a Jinrai (an Mass produced Arma that can match a Machina in the right hands), and he does more damage to the enemy by jumping out and punching it with his Factor enhanced strength than the Jinrai's weapons.
Unstoppable Rage: In response to Yajima's death. And, towards the end of the anime, in response to Emi's.
Blood Knight: As a kid he would used to get into fights under the pretext of "being an ally of justice". A recent battle in the manga hints that he still has that tendency.
Curb-Stomp Battle: His first two fights with Koichi consist of nothing but him beating the crap out of the poor kid. However, he gets on the receiving side of this trope in the anime when Emi gets in Linebarrel's cockpit.
Dark and Troubled Past: He grew up being raised by his sister and upon finding out he can't feel pain, starts getting into fights, and that eventually ends up getting him in trouble with the law
A 16-year-old girl who is the Factor of Painkiller. In the anime, she is already a member of JUDA, whilst in the manga, she is an idol singer, who decided to join in the mid parts of the storyline after Koichi saves her.
Rescue Romance: About the one thing her anime self and manga self have in common is her falling in love with Koichi after he saved her (though in different ways).
Senpai Kohai: After Koichi gets into high school, Miu turns out to his senpai. Ironically, sometime after they find this out, Miu becomes Painkiller's Factor, and she noted that this time, he's her senpai.
Yandere: The manga version of her is... different. In fact, she's so fucked up in the head that Painkiller made her its factor believing she was dying. She finally snaps after Kouichi disappears when the Time Skip happens.
The Endou twins
A pair 14-year-old twins who are both Factors for Deceive.
Cool Ship: The Shangri-La is pretty much a huge spaceship.
Easily Forgiven: Subverted in the anime, as Koichi does not forgive him for his crimes, but accepts to put his resentment aside and work with him for the greater good. Played straight in the manga, where Koichi does forgive him, and even offers to help him. Admittedly, his goals in the manga are different from the anime.
Heel-Face Turn: In the manga, he decides to try things the way his old friend Ishigami did, and leads the rest of his organization with the members of JUDA.
Emi, I Am Your Older Brother: Anime-only. In the manga, he was her father's live-in assistant, though it is mentioned that a young Emi did see him as a brother of sorts (as well as considered part of the family).
Never Got to Say Goodbye: The reason why he's so pissed off with Ishigami in the manga; he literally treated him like his own father, and is justifiably upset when he left them with no explanation immediately after mounting Juda.
17-year-old Factor of Talisman whose story (and indeed, personality itself) depends on the medium. In the anime, he captains Katou's 2nd Squad in place of the manga-exclusive Sanada, who loves inflicting pain on others. In the manga, he is the 72-year old leader of his village (having stopped aging at 17 due his being a Factor), who eventually decides to join JUDA's Special Task Force.
Childhood Friend of Koichi and Risako, who's protected the former from bullies since they were kids. His death was a major turning point for Koichi. He eventually comes back to life as the Factor to the Machina Apparition, and eventually joins up with his best friend.
A student at Koichi's school who is good at fighting and loves to flirt with cute girls. After being amazed at Linebarrel, he decides to join Hayase's group of friends (dragging along Furuya, who used to bully Koichi), dubbing them the "Hayase Corps." Eventually pilots a custom Jin-Rai (a production model machine created by Kiriyama Heavy Industries intended to replace Arma, and possibly, JUDA's machina) and joins up the members of JUDA.