Yu Nishinoya is one of the characters of the sports anime Haikyuu. “Haikyu!!” is a story of a boy Hinata Shoyo who is determined and focused on becoming an amazing volleyball player despite his short height. He is the protagonist of the series who is very courageous, cute, and a bit clumsy. To become a great volleyball player, he worked very hard and faced all the obstacles that came in his path.
Within a few months after its release, the anime became a fan favourite. This had a lot of reasons. The storyline, plots, moreover the bond between the characters was the major reason behind this love.
Yū Nishinoya was a second-year student at Karasuno High School. He served as the libero for the school's volleyball team and was referred to by his teammates as "Karasuno's Guardian Deity" for his remarkable skills. In case, you are familiar with the anime you must know that at the start of the first season it was revealed that Nishinoya left the team. The reason he left the team was none other than Asahi Azumane.
AsaNoya- The Fanship

AsaNoya is the slash ship between Asahi Azumane and Yu Nishinoya. Asahi's the 3rd year and Nishinoya's the 2nd year, both on the Karasuno High School volleyball team. Respectively, Asahi's jersey number's 3 and Nishinoya's jersey number's 4.
Also their positions: Asahi being the ace/wing spiker and Nishinoya being the libero, also pair nicely together. Throughout the series, both characters have a strong friendship, with Nishinoya always having Asahi's back and also the two help one another out during training and games.
In the first season, after Karasuno wins their first practice match against Aobajohsai, the team talk about how they're missing players, a libero and an ace. It's later revealed that Asahi left the club and Nishinoya got a week of suspension and was banned from club activities for a month. This happened back in March when Karasuno suffered a loss against Date Tech, where Asahi's spikes were completely shut out.
In Karasuno's gym, the two had a fight, both taking the blame for the team's loss. Days after, Nishinoya confronts Asahi about why he didn't come to the club the other day, and when Asahi still feels scared, Nishinoya tries to convince him to come back. But from the ruckus in the hallway, the Vice-principal interrupts them, but Nishinoya accidentally breaks the Vice principles plant, reasoning his absence.

Ever since that, Nishinoya's been passionate to play alongside Asahi again and even refuses to join the club without him at first. But after reasons from Suga, Daichi and the fact that Karasuno will play Nekoma, Asahi finally shows up and plays in a practice game, with him and Nishinoya being on the same side along with some of the alumni from Karasuno.
Although Asahi's a little scared at the start, Nishinoya tells him that he's right behind him to save any of the blocked balls. With that, their bond strengthens, they win the match and Asahi joins the club again. During the Tokyo training arc and up to the Spring High Tournament, Nishinoya helps Asahi with his serves. Also, Asahi helps Nishinoya by spiking his tosses/sets.
This is later perfected during the rematch against AobaJohsai in the Spring Tourney semi-finals when they win the 1st point of the game when Nishinoya tosses to Asahi and Asahi spikes.
Later on in the future, a flashback is shown of Asahi asking Nishinoya about his opinion about him going to study fashion in Tokyo.

In August 2020, Asahi and Nishinoya send a screenshot to Daichi and the others, showing that they were in Egypt, showing once again their strong relationship with each other. AsaNoya is shown as a loving and caring ship. Though they both have very contrasting personalities: Asahi being shy, quiet, wimpy and sometimes negative, and Nishinoya being loud, positive and full of energy, the two care for each other, and have each other's backs.
In fanart, AsaNoya is seen as a healthy/fluffy ship. This includes Nishinoya comforting Asahi when he's scared. Also, Nishinoya sometimes pushes Asahi to become stronger and to come out of his shell, while Asahi tries to calm Nishinoya down.
While Nishinoya is a loud and sunshine kind of person, Asahi is calm and smart. He is familiar with how to handle situations. The best thing about them is the sync between them which makes them look perfect together.
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