Cain

"Wherefore Cain was called, and he gloried in his wickedness."

- Glyph #6.

Cain was the first of Adam and Eve's two known sons, and the older brother of Abel, whom he killed in order to obtain a Piece of Eden that Abel possessed.

In relation to Cain's treachery, during the 21st century, Clay Kaczmarek referred to the Templar cross as the "Mark of Cain."

Biography
Cain was the firstborn of Adam and Eve, both human hybrids of the First Civilization. At one point in his life, Cain killed his younger brother, Abel, in order to steal the Apple of Eden in his possession. Cain's mark, which he was given for killing Abel, eventually became the symbol of the order he later founded, the Templars; a cross under which they united to collect more Pieces of Eden.

Clay Kaczmarek spoke of Cain in one of the Glyphs that he hid within the Animus data. He mentioned Cain's murder of Abel through quotes from the "Pearl of Great Price" scripture of the.

Trivia

 * The Templar pirate Jing Lang mentioned the story of Cain and Abel while talking to Vance Travers about the assassination of his brother, Upton Travers.

Reference

 * Assassin's Creed II - Glyphs #6: "Brothers"