That looks like Hakuno (male) but that might not be BB, it could be Kazuradrop since the commentary translates to 'worm space'.
Yeah, it's Hakuno from Foxtail - he wears a scarf over the uniform for a while. The BB is more complicated - IIRC, Kazuradrop uses it as a disguise, but she also has Melt use the "overlay" at least one time as a decoy.
