Watari has quite tan skin, with grey eyes and a similar coloured grey buzz cut. He is of an average height and medium build.
He appears to enjoy being challenged, smiling when Nishinoya repeats the same move he’d used, setting from the back row of the court. He is shown to be gentle and supportive of his teammates, trying to cheer up Kyōtani after the latter misses a point, regardless of Kyōtani's lack of proximity with the rest of their teammates.
Before becoming the libero, it is mentioned that Watari was a setter, which explains some of his moves and techniques, such as setting the ball from the back row. However, it is unknown if he has ever played as a setter for Aoba Johsai.
Karasuno High Team Formation Arc
Watari plays in the practice match between Karasuno and Aoba Johsai.
In the middle of the first set, Karasuno manages to bump it multiple times and send it over to the back of Aoba Johsai’s court. Although he is a libero, Watari sets to Hanamaki, and he is able to score. When Aoba Johsai is one point away from winning, Kindaichi tries to score against Karasuno but gets blocked. In an attempt to win the rally, and ultimately, the set, Watari manages to get the ball out of the court right before it falls to the ground. During the second rally, Tsukishima surprises Aoba Johsai’s blockers with two tips in a row. During the second tip, Watari gets annoyed at this, but still manages to save it.
During the next rally, Watari sees that he would need to receive Tsukishima’s hits again, and as he approaches to do so, Irihata yells at him not to get out of position as he still hadn’t seen what Tsukishima is going to do. However, Watari still does so and fails to bump Tsukishima’s slam. During the start of the third set, Takinoue and Shimada watch as Watari fails to save a free ball. As this happens, they recognize Aoba Johsai’s good defense, but also say that Karasuno just has the better libero. However, when Oikawa digs the ball and can’t set, he calls for Watari to do so and seems to be setting iwaizumi but instead goes for Oikawa. 
Two girls watching the match notice this, and Takinoue tells them that Watari's set wasn’t just a good set since there is a lot of regulations for this set, and Watari managed to dance around them without much difficulty, and while jumping as well. At this, Takinoue speculates that Watari may have been a setter before switching for libero. During a time-out, Hanamaki asks what they are going to do about Hinata’s quick, and Irihata just tells them to ignore it. So when Hinata is jumping, no one is targeting him, and Watari gets a clear view of where he needs to be to dig, which leaves confusion, letting Oikawa pull a dump.  When Aoba Johsai is one point away from winning the match, Hinata spikes to the other side, but Watari manages to dig it, surprising the audience. He manages to dig the next spike from Hinata in the next rally. Despite this, he fails to save the next one.
Spring High Preliminary Arc
Aoba Johsai vs Date Tech
During the match, Watari easily recognizes Koganegawa preparing for a setter dump (The anime would change this to Hanamaki) and bumps the ball for Oikawa to set. In the very same rally, Watari sets. As he does this, spectating Karasuno members wonder who he will set it to. In the end, he sets it to Oikawa. After Iwaizumi wins Aoba Johsai the game, Watari praises his teammate in awe.
Aoba Johsai vs Karasuno
During the first rally of the game, Watari is surprised at how Nishinoya could now set since he can do that himself. Shortly after, Watari fails to receive Hinata’s slide and he notices that Hinata has learned to figure how to pick his shots. During the second rally, Oikawa requests Watari to purposely botch his next pass to have a decoy lure Karasuno’s blockers in going to the left and letting Kyotani score. Watari and Kyotani successfully pull this off and Aoba Johsai wins the rally. Sometime later, Watari is the first one to be able to receive Yamaguchi’s streak of points with his serves. Nishinoya, who is watching, expresses admiration for the libero as he does this.
After Kyotani fails his spike, Watari attempts to cheer him up by being friendly with him, but the libero is quickly pushed away and Kyotani is subbed out. Not long after, Hinata is able to score past Yahaba. (this was a change from Watari in the shonen jump release) Near the end of the set Sugawara serves, but purposely aims at where atari and Iwaizumi are standing so that Watari would hesitate about letting Iwaizumi have it or not. After Kageyama scores a dump, Aoba Johsai requests a time-out, and Yahaba expresses how he wishes Kageyama could’ve shared his skills as a setter with him. Upon hearing this, Oikawa remembers back at how even though the efforts for his work may not appear right away, they could always show up another time if he still keeps practicing, and Oikawa tells this to Yahaba and Watari next to him, which leads the both of them to find that their captain has changed.
During the game’s final rally, Watari tries to keep the ball up, which he succeeds at but it goes into the net. However, Kyotani is able to save it. After Aoba Johsai’s loss, Watari breaks into tears. However, he is shown feeling better about himself when he gets ramen with the rest of the team. That night, he isn’t shown being overly remorseful over Aoba Johsai’s loss, unlike his other teammates, but he thoroughly studies the previous matches the team had.
Tokyo National Arc
With his team, Watari watches Karasuno's matches at Nationals in the school computer lab.
At the end of the series, Watari is shown watching the match between Argentina and Japan. He is now working at an aquarium in Kanagawa.
|High School Statistics|
He's confident in his setter abilities, and it's shown that he is fairly talented when he set the ball instead of Oikawa.
He also has moderate receiving skills as a libero. After the third years retired, he is assumed to be the strategist of the team.
Jumping Reach: 290 cm
- Favorite Food: Boiled eggs
- Current Concern: He'd like to build up more muscle.
- He shares his birthday with Hyakuzawa (3rd April).
- He is the oldest second-year student in the series.
- Shinji (治) - Govern
- Watari (渡親) - Person To Pass