Anas b. Malik reported that Allah's Messenger (ﷺ) said:There is never a prophet who has not warned the Ummah of that one-eyed liar; behold he is one-eyed and your Lord is not one-eyed. On his forehead are the letters k f. r. (Kafir)

Anas b. Malik reported that Allah's Messenger (ﷺ) 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 (ﷺ) said:Dajjal is blind of one eye and there is written between his eyes the word" Kafir". He then spelled the word as k. f. r., which every Muslim would be able to read