Who are those upon whose foreheads it will be written on the Day of Resurrection that they are despaired of God's mercy?

There is no authentic hadith (definition) that states the phrase "written between his eyes: despairing of the mercy of Allah" for someone who died in a state of disobedience. The strongest narration reported with this meaning is the hadith of Abu Hurairah: "Whoever helps in killing a believer, even with half a word, will meet Allah Almighty with 'despairing of Allah's mercy' written between his eyes." However, this hadith is weak. Furthermore, there are other narrations with this meaning, but they are fabricated and false.