Tensei really shouldn 't be as upset about this as he is. He got to see Ru-kun perform

Say It Ain 't So

in person already, after all. That doesn 't stop him from pouting ferociously when his little brother blurts out the bewildering events of their class performance well after the fact. Tenya doesn 't seem to know what to make of Ru-kun, which, at the very least, seems to be a sure sign that Ru-kun hasn 't yet induced a crippling gay panic within his little brother, but he figures that 's only just a matter of time. Ru-kun is a walking sexuality crisis.

And apparently Ru-kun will have plenty of opportunities to do so over the course of the school year, because according to his brother the scuttlebut among Class 1-A is that former s-rank cremation villain Dabi is now an assistant teacher at U.A. The thought seems unfathomable ' but everything about Ru-kun is already pretty unfathomable, so it 's rather on brand for the guy.