Abel is a Biblical figure in the Book of Genesis within Abrahamic religions. He was a younger brother of Cain, and the second son of Adam and Eve, the first couple in Biblical history. He was a shepherd who offered his firstborn flock up to God as an offering. God accepted his offering but not his brother's. Cain then killed Abel out of jealousy.
According to Genesis, this was the first murder and Abel was the first dead person in the history of mankind.
–Wikipedia