Picture, if you will, the scene of a school cafeteria. One emptier than it would be at any other time of the day, but a school cafeteria nonetheless. A school cafeteria filled with stores hawking tasty sustenance, mascot statues appealing to merchandising, and a small number of loitering students taking advantage of their temporary freedom from classes to grab themselves a quick meal to replenish their energy stores for the inevitable task of learning. Of course, there is a major difference between this scene and the school cafeteria you are likely picturing (beyond the fact that trainee Hunters would not be found so easily in some school cafeteria): there is an unfortunate lack of Shuai Taidan in your imagination.
That isn't to say, however, that there is a visibly "Taidanesque" presence in this cafeteria either.
Certainly, this larger-than-life Shuai Taidan should be one of loitering students in the cafeteria, but for all intents and purposes, the room seems bereft of anything larger-than-life, and one would suggest that Shuai Taidan isn't larger-than-life at all, if he could be present without anybody noticing.
Yet there is a simple explanation.
The reason for why there is no sign of Shuai Taidan, why nobody has noticed his presence despite his supposed larger-than-life nature, why there is no radiant aura of cheeriness filling up some corner of the room, is merely the fact that ...
... Shuai Taidan doesn't look like Shuai Taidan.
An unexpected answer, but one with an even more obvious answer:
Shuai Taidan is in costume.
Take a look at the small number of loitering students in this cafeteria. At first, you may have thought that the set with the qualities of "who could be Shuai Taidan" essentially boiled down to one discrete variable: "the boy who looked like Shuai Taidan and thus was Shuai Taidan". This, of course, would have been fallacious reasoning even had Shuai Taidan looked like Shuai Taidan given the presence of those with shapeshifting or illusionary powers present within the halls of Beacon Academy. Yet that is not as relevant to the discussion as the fact that yes, Shuai Taidan does not look like Shuai Taidan.
And thus, the set of "who could be Shuai Taidan" expanded in scope from an individual to every single one of those loitering students. After all, if none of them looked like Shuai Taidan, and Shuai Taidan didn't look like himself, then everyone was a candidate for being Shuai Taidan.
(Except for your boyfriend, Plank. Because quite unfortunately for your case, Shuai Taidan is really just a flat, 2D creation made up of words and copyrighted images, and not actually part of the set consisting of "actual real humans who you could feasibly date".)
So of those loitering students, who is in fact Shuai Taidan?
It's not the silver-haired hipster with sunglasses, because he is far too tall to be Shuai Taidan, even if platform shoes were involved.
It's not the cleaner wiping gunk off the tables before more students arrive, because Shuai Taidan's shift isn't until later in the week.
It's not even the black-haired beauty inexplicably in a ballgown, because Shuai Taidan isn't crossdressing today.
What's the answer then, you may ask?
He's one of the supposed mascot statues.
If it comes as quite a surprise, then you likely share the sentiments of many of the students present in the cafeteria. They too assumed that the grumpy-faced bear wearing kevlar was merely a statue owned by the sweets store, but the sudden motion of said bear's feet proved them to be incorrect. It was no statue, but in fact a costume.
A costume containing Shuai Taidan.
A Shuai Taidan who had decided to stop loitering in a costume and start waddling out of the cafeteria.
Witnesses could only stare after him in shock.
And once he, clad still in costume, disappeared from the cafeteria's confines, a conclusion could be settled upon:
In this cafeteria, the set of "who could be Shuai Taidan" no longer contained any individuals.