He is a tall man with green eyes and spiked hair; with a pair of eyeglasses. He appears to be wearing a green yukata cloak and inside is a black uniform with green lights.
In the past, Kengo did not have his hair spiked up; and is combed down. After the incident that caused the loss of Sahanasaki's students, he now has a large scar on his back which resulted from shielding Kankuro.
Kengo is known to be rather irritable. He is also shown to have a miserly personality and is very greedy when it comes to money; shown when he charged Arata Inanaki 10000 yen for a BonBonBina Magical Girls shirt because the shipping and handling fee in the anime, and charging the mainland exorcists per his services in the manga. Furthermore, he would often include moneymaking as a primary reason to doing jobs; and sometimes would compulsively calculate expenses (or losses) with his abacus at certain instances.
Despite his annoyance towards his friend and fellow Guardian Kankuro, he has shown a great degree of care and guilt about what happened in the past; as well as a form of anger that stems from the way of life Kankuro lived afterwards. His desperation to turn Kankuro back to how he was in the past was great enough to force him to tempt Rokuro in revealing Kankuro's weaknesses. While somewhat still forceful towards Kankuro after the Castle Games, he shows that he cares about him greatly; saying that the void inside him left by the accident would never heal if Kankuro himself never tried to recover.
Kengo is seen being treated by Kankuro.
Powers and Abilities
Because he is from the Ujii House who excels in barrier spells, he holds the title of the strongest defensive and barrier spell caster.
- Gentei Bukyu (玄帝武鬮 Gentei Bukyū?, lit. "Occult Emperor, War Lottery"): Kengo enchants his abacus with Steel Shell Expose Charm (鋼殻顕符 Kōkaku Genpu?).
- Jin no Kikkyo: Senpaku (陣の亀鏡•殲魄 Jin no Kikkyō: Senpaku?, lit. "Camp Turtle Mirror: Spirit Massacre"): Kengo pours out water, which is propelled through a target and then reflected off several mirrors to hit the target multiple times.
- Gentei Bukyu Mystic Gear Equip (玄帝武鬮 纏神呪 Gentei Bukyū Matoi Kajiri?):
- Jin no Kisho: Bakujo Maten Koro (陣の亀墻•縛錠摩天光牢 Jin no Kishō: Bakujō Maten Kōrō?, lit. "Camp Turtle Barricade: Binding Prison of Divine Light"):
- Jin no Kikkyo: Senpaku - Aratame (陣の亀鏡•殲魄•改 Jin no Kikkyō: Senpaku - Aratame?, lit. "Camp Turtle Mirror: Spirit Massacre - Modified"): 
- The name Kengo means "law" (憲) (ken) and "sturdy, strength" (剛) (go).
- Twin Stars Exorcists Manga; Chapter 31, page 11-12.
- Twin Stars Exorcists Manga; Chapter 31, page 13.
- Twin Stars Exorcists Manga; Chapter 42, page 41.
- Twin Stars Exorcists Manga; Chapter 65, page 14-15.
- Twin Stars Exorcists Manga; Chapter 65, page 12-13.
- Twin Stars Exorcists Manga; Chapter 66, page 21-22.
- Twin Stars Exorcists Manga; Chapter 66, page 23-24.