Tamanawa is the newly elected Student Council President of Kaihin Sougou High school. He is a 2nd year.
In the anime, Tamanawa is seen wearing the uniform of Kaihin Sougou High school that is composed of a white dress shirt, a light blue sweater with two dark blue lines at the top, and a red tie under a navy blue blazer and pants.
Tamanawa is a somewhat pompous person, who often uses complex English words in some of his sentences. Hachiman observed that he uses many similar meaning words (synonyms) in English and Japanese in quick succession.
Hachiman and Yukino note he just likes to be in charge and lacks any real ideas or convictions.
Hachiman also feels that neither Tamanawa or any other student council members wanted to take full responsibility of the Christmas concert because of a fear of failure. Tamanawa comes across as really indecisive and unable to manage time well.
He seems a little dense or stubborn, when Hachiman tries using Tamanawa's own lingo to progress the Christmas Collaboration meetings he still wouldn't commit to anything. It's not until Yukino directly addresses his inability to act do they start to get things done.
Although Tamanawa wont commit to any one idea for the Christmas Event, he is eager to involve and please as many people as possible. Indicating a rather sociable side as he happily welcomes new members such as Hachiman, Yukino, Yui, and the elementary school students.
Tamanawa is likely a popular figure in his school, since he was elected as president of student council. He also managed to recruit his own friends like Kaori Orimoto to come and help.
He isn't a very experienced leader and is very indecisive, however, he is able to rally allies to his cause, showing skill in charisma. His friends and fellow council are almost blindly attached to his ideas and rarely disagree with him.
He has an impressive vocabulary of English and Japanese business words that he uses often.
Tamanawa has good communication skills with the exception of his complex words that often confuse others.
Tamanawa was seen capably directing his staff during the Christmas Event's play.
The running gag is every time he speaks, he makes swift, odd hand movements.