Board Thread:General Discussion/@comment-5719892-20171024211142/@comment-31337598-20171121161609

Lucastv719 wrote: ^ I think in terms of Haizaki talking to Asuto and Yuuma as upperclassman will follow around the same path as Tsurugi, as he begins with no honorifics at all, if any later on, he'll probably just add a "san" instead of "senpai." Besides, they don't use san/senpai all the time-Tsunami was the oldest back in original Inazuma and the only ones who some to him with honorifics were the 1st years. I Believe that Tsurugi called Nishiki with Senpai, at least in Chrono Stone

and in the first episode of Galaxy he called Shindou with san.

well Tenma who was used to call Shindou with senpai called him san in Galaxy, i think they became 2nd year students in Galaxy