ヤンデレ  Tag

From Wikipedia:

A term for a person who is initially loving and caring to someone they like a lot until their romantic love, admiration and devotion becomes feisty and mentally destructive in nature through either overprotectiveness, violence, brutality or all three combined.[...] Yandere characters are mentally unstable, incredibly deranged and use extreme violence or brutality as an outlet for their emotions. Yandere are usually, but not always, female characters.

This tag applies to:

• Songs where characters are portrayed as yandere
• Albums with multiple songs featuring yandere characters
• Artists that make songs featuring yandere characters
• Vocalists who canonically have a yandere personality