>>535059280
>>535061591
>"the process through which a fictional character's essential traits are oversimplified and exaggerated to the point where they constitute their entire personality"
I don't know what else you'd call the act of Aru, and especially PS as a whole, having their retardation turned up 200% and failing to do something Kayoko, at a minimum, would do for plot contrivance purposes.
Unless you wanted to call it plain old bad writing.