|“||We of Tachikawa Unit don't have the free time to personally partner with a B-rank. After all, we're A-rank #1.||”|
Yuiga is a boy with shoulder-length black hair parted in the center, and slanted eyes with small pupils. When he is in trigger mode, he wears a black long coat with thin red stripes on it and a Border emblem patch on his left sleeve, just like the rest of his unit.
Yuiga has a tremendous amount of pride in the fact that his unit is the top of the top, using it as a superiority of sort. He is cocky and smug; however, he is easily brought down by his teammates and his proud persona is easily blown. He is childish and whiny.
- (To Osamu) "We of Tachikawa Unit don't have the free time to personally partner with a B-rank. After all, we're A-rank #1.) " 
- "Takeru" (尊?) means "respect, revere, venerate, honor". "Yui" (唯?) means "only, yes", while "wa" (我?) means "our, us, I, me, my, we". Together, it can mean "respect only to myself", which describes his personality and attitude.
- He likes high-rank French cuisine and being respected.
- His father's company is Border's biggest sponsor, so when he insisted on joining an A rank squad upon enlistment in Border, the executives put him in Tachikawa Unit.
- He shares his family name with Makoto Yuiga and his son Tadashi Yuiga from Talented Elite Jin.
- Additionally, he bears a resemblance to Tadashi Yuiga.
- According to Border Briefing File, Yuiga is both Border's least popular and the most concerned with popularity, while Raijinmaru is both the most popular and the least concerned with popularity.
- He wasn't present during either Headquarters' raid to take Yūma's Black Trigger or Border's operation to thwart Galopoula's invasion, possibly due to his inexperience.