The idea of the 1000° knife was originally from a YouTuber called "Fire Sweet Fire". In his videos, he heats a knife and starts cuting objects like Coca Cola Cans, phones, firecrackers and crayons. Eventually, it became viral across YouTube.
Although the videos claim to be having 1000 degree knives, there is no proof to support that the knives are actually superheated to that exact degree. The 1000 Degree knifes are mostly done by MrGear now. We have no idea if the knife's degrees are Celsius, Kelvin or Fahrenheit.