Anas b. Malik reported that Allah’s Messenger (may peace be upon him) said: There would be written three letters k.f.r, i.e. Kafir, between the eyes of the Dajjal.

Anas b. Malik reported that Allah’s Messenger (may peace be upon him) said: There would be written three letters k.f.r, i.e. Kafir, between the eyes of the Dajjal.
Source: HOTD