Adam was a hybrid human-Isu, conceived in order to preserve the DNA of the technologically advanced beings. He was also one of the first Assassins, along with Eve. In addition, Adam is a distant ancestor to both Clay Kaczmarek and Desmond Miles.
In 75,010 BCE, Adam and Eve, another hybrid, rebelled against their creators. As hybrids, the two were biologically immune to the effects of the Pieces of Eden on their brains, lacking the neurotransmitters upon which the Pieces of Eden acted and that would have compelled them to obey.