Koichi Kimura (Japanese name: Kouichi Kimura) is a character from Digimon Frontier. Originally brainwashed to fight the DigiDestined as Duskmon, he breaks free from Cherubimon's control and fights alongside his twin brother, Koji Minamoto. He holds the spirits of the legendary warrior of darkness, Loweemon.
He is voiced by Kenichi Suzumura in the Japanese Version and by Crispin Freeman in the English Version.
Koichi is a young boy with pale skin, short black hair that is parted to the sides of his face, and dark blue eyes. He wears a red long-sleeved shirt under a green open button-up shirt with short sleeves, white pants, and green sneakers with yellow streaks. He wears a blue cap with a white symbol on the front in the Human World, but he loses it upon his transition into the Digital World. His face is identical to his twin brother, Koji.
Beside he is Koji Minamoto twin brother, he share different personality with him. Koichi overall is gentle, calm, mature young boy who wants to do the right thing but is prone to burying his problems in his heart.Within his gentle persona, Cherubimon state that he is has a great potential for darkness, born from his resentment of his twin. Which causing him being used and manipulated by Cherubimon and turn him into ruthless and unstable minion name Duskmon.
As Duskmon, he become a loyal minion of Cherubimon. He know very cold, ruthless, merciless, aloof due his influence and also unstable. After his memory slowly recover and know that Koji is his twin brother, he tell to Cherubimon that he unable to kill him, causing him become angry with Duskmon and manipulated him once again for killing Koji to release all his and his mother "pain" which is causing from his Father. But thanks to Koji as Beowulfmon and Takuya motivation to Koji, he finally able to be save by them and permanently release from Cherubimon influence.
Although he no longer to be villains and become his former self, Koichi still hold his Spirit of Darkness with a new Spirit named Lowemon and Kaiserleomon. As digidestined and their allies, he become more brave and willing to do anything to save his friends and his brother even he must to sacrifice himself. During the battle with Lucemon, he sacrifices himself to save his friends and his brother from Lucemon’s fatal attack, it in the end, Koichi was revived.
- He is similar to Ken Ichijoji.
- His English Voice Actor, Crispin Freeman is best known voicing as Thomas H. Norstein from Digimon Data Squad, Itachi Uchiha from Naruto/Naruto Shippuden, Shizuo Heiwajima from Durarara!! and Tsume from Wolf's Rain.
- He is the only Chosen Child in the animated Digimon series to 'die' in battle, although he is revived at the end of the season.
- Originally, Crispin Freeman was considered to voice Koji, but was reconsidered and was cast to play Kouichi instead.