Riddle first exposure to Sebek is overhearing Sebek scold his fellow first-years for whispering during the opening ceremonies, saying they need to comport themselves “with dignity” and that their “indecent conduct brings shame down upon all freshmen, myself included! Ceremonies require a certain sobriety. We may yet be callow, but we are all mages in the making. Act like it!”
Impressed by Sebek’s ability to make the other students settle down Riddle says “At least there’s one sensible head in this year’s class. If he ends up in Heartslabyul, I may put him in charge of the freshmen.” Riddle is shocked by the “abrupt character turn” he sees when Sebek is assigned to Diasomnia.
(For the curious: No, Sebek did not say “awww yeah, baby! Woohoo!” in his original dialogue. He gave a stuttering response that is similar to “I-I-I did it!”, “I got in!”, etc. There is a pattern with Sebek of pretending to be wholly confident while, in reality, being very uncertain. His original response sounds more relieved; a rare moment where we see he had actually been worried. This is why the look on his face may seem kind of mismatched with his English line.)
During Riddle’s first interaction with Sebek, Sebek accuses him of being “a spy, sent to uncover Diasomnia’s deepest secrets”. Riddle responds with “I mistakenly believed you to be a man of diligence and decorum”.
Riddle also says that “Like all other Diasomnia students, your well-mannered facade belies your supercilious nature”, which Silver follows with “It is because of people like (Sebek) that Diasomnia’s reputation suffers”, which is some fascinating insight into Diasomnia’s reputation at the school.
Silver assures Riddle that “Diasomnia’s teachings have nothing do with this. Sebek is…a special case. Surely I wasn’t that bad.”
Sebek insists, “I will not be reprimanded by you, Silver! Indeed, I have done nothing wrong…If you have some sort of complaint, then state it!”
Riddle says that while he understand that “every dorm has its own customs and ways of thinking” Sebek will need to adhere to the ideology of the equestrian club if he is to join and obey upperclassmen, and Sebek vows “to obey any orders, within reason”.
Riddle says that he sees Sebek takes riding seriously, and Sebek explains that this is because riding “is an essential skill if I am to serve under Malleus”.
Sebek insists upon seeing the other club members’ skills before deciding to join the club, as “If I am to make myself maximally useful to Malleus, I would be better served by weight training than riding with a bunch of amateurs”.
Sebek submits his entry application for the club immediately after seeing Riddle’s riding abilities.
Much like Trey observed during Halloween, Riddle says that he sees Sebek is “single-minded and straight as an arrow”.
Twisted Wonderland Reference Note 