Though he took sides with Serizawa group due to their hometown Mito, he was also getting along well with Okita and Todo from the Kondo group because of his innocent character and it is considered that he was kept in Sumiya on purpose.
水戸出身であることから芹沢一派に与していたものの、素朴な人柄から近藤派の沖田や藤堂とも仲がよく、粛清の際にわざと角屋に引き止められた、という解釈である。