Sankaku Channel/yandere

Yandere (ヤンデレ) is a Japanese term for a person who is initially very loving and gentle to someone before their devotion becomes destructive in nature, often through violence. The term is derived from the words yan (ヤン) meaning a mental or emotional illness and dere (デレ) meaning to show affection. Yandere characters are mentally unstable, often using extreme violence as an outlet for their emotions.