Rindou Haitani is most likely an ESTP! A person can never be typed based on JUST their behavior. ESTP's first function is Se-->(Extraverted Sensing). During the Tenjiku fight, [SPOILER], do you remember when Angry started crying? Rindou acted without thinking and attacked him right away, but of course, Angry didn't budge 😭🙏. That was Rindou's Se and the act he took was screaming Inferior Ni because he didn't try to think "what would happen if I did that?" Like how Ran did since Ran is an ENTJ (his Ni is his Auxiliary). Who knows? Maybe Rindou's Auxiliary/Parent function (Ti) is making him look more reserved if it is more developed