Eijiro is a very boisterous, outgoing guy with a fondness for the concept of manliness, often using the terms "manly" and "unmanly" to describe stuff he does or doesn't like. Those who showcase a noble, brave or determined attitude tend to emotionally move him to tears, quickly earning his complete admiration, respect and friendship. Similarly, he will call out traits that are the opposite of that, such as cowardice and dirty play. He is also a big fan of Crimson Riot, a retro hero that he takes inspiration from, including his own hero name.

Eijiro is honest and kind-hearted, with All Might praising his heroic spirit. In addition, he seems capable of making friends with most people, as he is one of the few classmates who is friends with both Katsuki Bakugo and Izuku Midoriya. Eijiro is very dedicated to his friends and is even willing to break the law and the rules in order to help them, showing regret if he becomes unable to do so.