wtf is a dere scale
Dere Dere (デレデレ)
Meaning to become 'lovey dovey'
If you merge this with 'Yan' and 'Tsun' you would get..
Yandere (ヤンデレ?)
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 yanderu (病んでる?) meaning a mental or emotional illness and deredere (でれでれ?) meaning to show affection. Yandere characters are mentally unstable, often using extreme violence as an outlet for their emotions.
Tsundere (ツンデレ?)
a character type whose personality is initially combative but eventually becomes loving and emotionally vulnerable.