SOTUS manga volume 3 features story by BitterSweet and art by Kei.

While Arthit continues to train his juniors under the SOTUS system, his previous strictness has faded away and he’s come to earn their affection. Later, Kongpob enters Arthit’s room, only for a misunderstanding to occur and for Arthit to distance himself from him. But Arthit can only escape for so long before he realizes his true feelings for his junior… The sweet romance between upperclassman and underclassman comes to a close in this finale.