This question is about speculations that might have taken place in Christianity on the matter of Cain's destiny - whether he will be in the kingdom of God (which means that he is saved) or he will go into eternal perdition.
Have there been any speculations on this matter in Roman Catholic, Orthodox or main-stream protestant Christianity (by main-stream protestant Christianity I mean those who believe that Jesus is both the Son of God and God - the same God as God the Father is - but don't consider themselves to be a part of Roman Catholic Church or Eastern Orthodoxy)? If yes, can you, please, share them here.
Cain was the first murderer in the human history.
The following verse speaks not in favor of Cain:
From the blood of Abel unto the blood of Zacharias, which perished between the altar and the temple: verily I say unto you, It shall be required of this generation (Luke 11 :51)
However, I don't see any verse in the Bible pronouncing clearly that Cain will go into the eternal perdition. Or, perhaps, I am reading the New Testament in to the Old one here?