Sensei to Shoujo Soudou series

(先生と少女騒動, translated as Scandal Between the Teacher and the Girl) is a song series created by Wonderful☆Opportunity, being composed by Minus-P and illustrated by domco.

Background
The series shows the sickly and twisted relationship between a teacher (Len) and his student (Miku). Although it seems the teacher just is taking advantage of an emotionally vulnerable girl, the reality may not be as it seems.