While he lacks size, stamina and strength, he is extremely adaptable and receptive to Tsuji's orders, especially when he was the first person who witnessed his knowledge when he quickly defeated every member of Oodachi High using simple dodges except Hinomaru. and weakness (Tsuji's asthma flaring up after beating Hinomaru).
Due to his adaptability, he was able to quickly abandon his head-on style, opting for more deceptive and defensive moveset without overexerting himself physically. Also, he is surprisingly good at playing the hustler. Because the crowd expects him to lose, he plays to the role, reverts to the head-on style until the finals, or when the team is losing to surprise everyone. He tried the move against Mamiya Keiichi, where he leaps into his blind spot, and tries to push him out of bounds from behind while feinting a Russian leg sweep, but Keiichi manages to recover as the captain warned him of the plan.
Kei also thinks his style is 'dirty', because he must find any way possible to win with seemingly no specialized, defined or refined technique or style. Yet, Hinomaru believes Kei's style is the opposite to his, which impresses him, because Kei's counter-attack and reactive reversal style is not something Hinomaru want to pursue, but it is a style that Kei would pursue without hesitation. He even goes as far as copying Sanada Yuuki by deliberately false-starting, twice.
He took his psychological warfare further against Mamiya Keiichi. Firstly by the two false starts, but then walks towards his own edge of the ring by not engaging with him, but not in a taunting way, before suddenly clapping, which sets up his dodge and push combos.
He has played the flute since he was 6 years old.
- Kei Mitsuhashi vs Mamiya Keiichi
- Kei Mitsuhashi vs Ushio Hinomaru
- His blood type is A.
- He is voiced by Murase Ayumu
- Aside from playing the flute, he likes reading novels. Like Hinomaru, he also likes studying history, as shown in episode 12 of the anime, where they convinced Tsuji to visit Nagoya Temple, while the Gojo sublings and Kunisaki went off to find Nagoya Cuisine. However, he is not good at history, when he admitted the fact when Tsuji is worse at history than he does.
- In the case of simultaneous landings, the match will restart. Kei lost the restarted bout to Mamiya Keiichi.