Futo's facial expression is actually sort of secondary creation of yajuu_senpai, as the Chinese character "首" looks very similar to yajuu senpai's yelling face. So I added this tag.

Shchjen said in comment #2614122:
as the Chinese character "首" looks very similar to yajuu senpai's yelling face

Which also means that this Chinese character need not and must not be translated, since it's purely pictographic.