As of November 2018, he is currently working as a manga artist.
During his time in high school, Udai appears to be around less than 170 cm in height and has messy curly black hair in a similar style to Hinata. In Saeko's flashback, he is also seen with dark grey eyes. During games, he wore Karasuno's volleyball uniform with the number 10.
During the Final Arc, Udai is shown to have let his hair grow past shoulder length. Although excited throughout the Jackals vs Adlers game, he has signs of weariness that most likely resulted from the stress of upcoming deadlines for his manga series.
Saeko Tanaka described him as a mischievous person and one of the "bad kids" whom she would've gotten along with. However, in the anime, she also claimed that he didn't stand out. When on the volleyball court, he radiated an intense aura of confidence and pride in being his team's ace whom his teammates could rely on in games.
In the current day, he seems to be more relaxed and easy-going; possibly as a result of having retired from volleyball after high school. He doesn't show a strong attachment to his past title of the "Little Giant", freely admitting that he wasn't as strong as he used to believe and that players such as Kōrai Hoshiumi are better than he ever was. While watching the game between Kamomedai and Karasuno, he mostly exhibits a light-hearted enjoyment of both sides' abilities without appearing too concerned about the outcome of the match.
Udai is an alumnus of Karasuno High and its former ace whose reputation was well known by many from Karasuno and individuals from other locations and prefectures during his time on the team and for several years after.
According to Keishin Ukai, Karasuno was at its peak when Udai played for the team. Initially, Udai used to frequently get blocked, but halfway through his second year his abilities started developing and he created his own playing style when he started hitting the ball in between blockers' arms and using deflections. This eventually helped lead Karasuno to nationals where he unknowingly became the inspiration to Shōyō Hinata.
Tokyo Nationals Arc
Karasuno vs Kamomedai High
Udai is revealed to be the Small Giant when he attends the Spring Tournament as a spectator after hearing about Karasuno making the quarter-finals. He manages to spot Akiteru from the crowd and accompanies the rest of the Karasuno alumni to the arena. Saeko introduces him to Hinata, who eagerly greets him and inquires about his current volleyball activities.
However, Udai admits that he had stopped playing volleyball after he graduated high school due to other interests as well as not having gotten many offers to join any college or professional teams. When Hinata is called to return to the team, Udai refers to Hinata as the new Little Giant. When learning that Kamomedai also has a player whose height is in the 160's, Udai calls the match a battle of the Little Giants but is further surprised to learn from Akiteru that Hinata is actually a middle blocker.
Udai is instantly taken by surprise at Hinata's quick attack as well as Karasuno's synchronized attack. He tries to cheer Saeko up when her brother missed his first serve. After watching Hoshiumi set to Hakuba, Udai admits that he had thought himself as a talented player throughout middle school and high school. Knowing his height put him at a disadvantage, Udai honed his technical abilities in order to compete with those taller than him. He is aware that Hoshiumi himself must understand this same thing of the world being both fair and cruel. When Kamomedai wins the first set, Udai comes to the conclusion that Akiteru's earlier statement of Udai and Hoshiumi being similar is false. Udai would later begin to relate to Asahi after being shut-down by Kamomedai's blockers, remembering the pressure that comes with being the ace.
Shortly after Sugawara is subbed out of the game, Saeko questions why the Karasuno team didn't use the method with the blockers that they did with Ushijima in which they had the ace facing their tallest wall. Udai explains that, to someone like Hoshiumi, the wall can simply be a target or something he can tool to his advantage by using a block-out. He would compliment her on knowing so much about volleyball but Saeko would explain that she became so knowledgeable from being around Akiteru, Shimada, and Takinoue. After witnessing Tsukishima dodge Hoshiumi's spike that would win the set for Karasuno, Udai is among those shown being taken by surprise by the act and Tsukishima's grinning expression toward Hoshiumi.
When Karasuno eventually lost the match, Udai felt confident that Hinata has not given up in his desire to continue moving forward. He would then be amused when Saeko mentions how everything leading up to this point was due to Hinata having seen him play at Nationals and he playfully remarks how he's created a monster.
As of the Final Arc, Udai has become a manga creator and is working on Zombie Knight Zom'bish. He goes to the game between the Schweiden Adlers and MSBY Black Jackals with Akaashi as they appear to now be co-workers. At the end of the match, Udai reveals that Zombie Knight Zom'bish is nearing completion but he has an idea for a new series he would like to work on. He and Akaashi interview Bokuto after the game but Udai is confused at the behavior between the two Fukurōdani grads.
In his final appearance, Udai appears to be working on a new manga series based on volleyball called Meteo Attack.
He was blocked constantly during his first year and didn't develop his set of unique skills until his second year at Karasuno. However, after he improved his abilities, he became peerless in mid-air battles. He has been said to have incredible jumping ability. Since he was no match for the blockers in height, he developed a play style using block-outs, where he intentionally aims for the small gaps of a block and the blocker's fingertips so that the ball would ricochet. That was how he conceived his battle against other blockers.
In the past, Ukai Ikkei gave the Small Giant additional training to help him develop other skills to make up for his lack of height. Karasuno had the best team in its history when the Small Giant was on the team.
After the time skip, Udai and Akaashi work together. They attend the Adlers and Jackals game together where they each take notice of Hinata's increase in skill and later would interview Bokuto together.
- "Y'know? Back then... I thought I was really good too." - (To Akiteru Tsukishima, Volume 39 Chapter 343)
- "I like to think that, across both middle and high school, I was one of the higher-level players back in Miyagi Prefecture. I was well aware that I was the Ace, and I was confident I deserved to be. But this is Nationals. The further up you go here, the bigger, the faster, the smarter your opponents get. I thought I had to rely on skill and technique to make up for my lack of height. But you know? Anybody can have good skill and technique, tall or short. All you have to do is practice. The world is fair, but at the same time it's completely unfair." - (To Akiteru, Volume 39 Chapter 343)
- "Know your weaknesses. Accept them. Forget the weapons you can't wield. Find all the ones you can... and carefully, persistently, hone all of them to a wicked point. That is what it means... to be a Little Giant." - (To himself, Volume 41 Chapter 362)
- "I guess I might've made a monster then, huh? I kind of like that." - (To himself, Volume 42 Chapter 368)
- Udai (宇内) - Within the cosmo/sky.
- Tenma (天満) - Fulfilled heaven.