Section Chief of Problem Solver 68 and student of Gehenna Academy.

Unlike the rest of the group, Kayoko is not one with ill intentions however she's often misunderstood due to her natural facial expression.
Normally keeping silent against these misunderstandings, this likely leads to furthering her scary image.

The "Section chief" of Problem Solver 68 

The "Section Chief" of Problem Solver 68 and student of Gehenna Academy.

Unlike the rest of the group, Kayoko is not one with ill intentions however she's often misunderstood due to her natural facial expression.
Normally keeping silent against these misunderstandings, this likely leads to furthering her scary image.