Part of what made this manga exciting is seeing the subtle hints from the beginning that Kanna is an absolute psychopath, possibly brain damaged, who only appears to have human emotions because people see her acting deredere for Rokudou.
Not sure how I feel now that she apparently actually does care about others.
Damn, Ranna sounds so stupid. She's so lucky she met Rokuduo with his OP power activated. Otherwise, she would just continue smashing people until she gets put down, or grow old and die alone if no one stops her. Lol.