Something that can only be defined by you. Not by somebody else.
Nobody can define the meaning of life for you because for everyone it is different. I believe the meaning of life is to challenge what is fated to happen to all of us (Death, Destiny, etc). Others would say the meaning of life is to find the meaning of life.
One of the sons of Adam and Eve and possible the first vampire. After he killed Abel he was banished and nature would no longer support him with fruits and plants to eat. Although it doesn't say what happened to him after his banishment he may have had to result to cannibalistic behavior to survive thus becoming the first vampire.
Cain was marked so that no person would help him and nature would not support him.
In the Book of Lillith (one of the apocryphal books of the Bible) she was Adam's first wife but refused God's word of male dominance and proved it by being on "top" during intercourse. She was banished from the Garden of Eden and was taken in by Satan-el to be one of his many wives.
The Book of Enoch, The Book of Razi-el, and The Book of Lillith are supposedly lost chapters from the Bible and remain unconfirmed in their origin. They have however existed for many centuries.