Well Jan-poo's theory seems irrefutable for now, and there are signs which kinda supports them.
Anyway. Finally I also have realized Pantsu's true identity!
Spoiler for HEAVY SPOILER!:
HE IS
JACK BLACK!
Jack Black must be an enthusiastic fan of the the
Cincinnati Reds (note the same icon), and that's why he wears such a shirt! As for his missing trousers, and WTF is he doing in Japan, I have no theory yet, but there are still 3 episodes and a movie left to explain those informations.
Sorry for spoiling all the fun!
