Neito and Yosetsu haven't interacted much, but they seem to be friends. Like most of his classmates, Yosetsu dislikes Neito's sarcastic and obnoxious personality, but he seems to tolerate him and keeps him in check when Itsuka Kendo is not around.
They were first seen together during their Class's preparations for the Cultural Festival. The two of them, along with Tetsutetsu, were making preparations for the Class 1-B play when they ran into Izuku Midoriya, Mirio Togata, and Eri. Neito starts teasing Midoriya and his class, before laughing maniacally. Yosetsu appears behind him with a large stick and knocks him out.
Once Neito was unconscious, Yosetsu slowly picked him up by the arm while apologizing for Neito's attitude, explaining that Neito was even more unbearable than usual since Itsuka was busy preparing for the beauty pageant and couldn't keep him in check. He then takes him back to his class while Tetsutetsu Tetsutetsu says goodbye to Midoriya.
Later before 1-B's play, Yosetsu and Tetsutetsu go along with Neito to check on Itsuka. Once there, Neito laughs and compliments Itsuka's outfit for the beauty pageant, explaining how he entered Itsuka in the first place and plans to overthrow 1-A. He begins laughing maniacally, and Tetsutetsu stares at Yosetsu whilst pointing at Neito as if asking him to do something. Yosetsu waves him off and lets it happen.
During 1-B's play, Yosetsu was behind Neito with Nirengeki Shoda as they performed. When the beauty pageant performances were over, Neito hopped on the stage and began yelling for everyone to vote for Itsuka. Yosetsu was left to hold him back and exclaim that she'd be disqualified for this.
During the Joint Training, Neito begins taunting the Class 1-A students. Yosetsu and Itsuka prepare to stop him, however Shota Aizawa beats them to it and does so by strangling him. It upset Yosetsu to see Neito choking, showing that Yosetsu truly cares for him.
Due to the little interactions shared between the two (and Class 1-B’s lack of screen-time), Monowase is not relatively popular within the MHA/BNHA fandom, and is thus considered a “rare-pair”. Additionally, it is overtaken by AwaMomo on Yosetsu’s part. However, it has gathered attention like any ship, and holds its own when it comes to choosing a (romantic) partner for Neito.