Sai is a person whose emotions were suppressed by years of training in the Root. He became accustomed to seeing himself as a tool, without his own name, and to obeying orders without thinking. Due to lack of social experience, he often speaks his mind without realizing that his words can hurt, and genuinely wonders why people get angry. Trying to establish connections, he turns to books and uses methods such as inventing nicknames, which at first leads to awkward situations. Over time, observing Naruto and his relentless effort to bring back Sasuke, Sai begins to understand what attachment and the pain of loss are. This helps him awaken memories of his brother Shin and experience genuine emotions for the first time—anger, sadness, joy. He is very observant, quickly notices details and senses the inner state of others, even if they say nothing. By the end of the war, he completely rejects the ideology of Root and begins to value friendly ties, seeking to forge his own identity.
