Was Crake a hero or villain?

Whether Crake was heroic or villainous depends upon which Crake is the subject of discussion and examination. Just as there are two story lines in Atwood’s novel, there are also two Crakes: one is the godhead immortalized in Snowman’s invented mythology for the genetically-modified Crakers, while the other is an extremely gifted scientist.
Crake the godhead is an illusion woven by Snowman as he attempts to protect the Crakers and grapple with the realities of his postapocalyptic life. To the Crakers, Crake is a positive, life-giving force. One might argue how many of them could view Crake as a hero.
Crake the man, however, rivals Victor Frankenstein in his desire to manipulate humanity. Although professing a desire to end human suffering, Crake’s efforts to do so are morally and ethically objectionable. Take his BlyssPluss tablets, for example. The libido-enhancing pills owe their success to their human test subjects: impoverished sex industry workers. The pill also contains a contraceptive that causes sterility, as Crake wishes to control the world’s overpopulation, but his subjects are unaware of this ingredient.
His experimentation with human embryos, which ultimately results in the creation of the Crakers, is equally objectionable. Crake, a purist in all things scientific, tries to create a race of super beings that will be free from lust and other romantic inclinations, as well as any predisposition to the arts, religion, or philosophy. Because he believes science is superior to all else and possesses a superior intellect, Crake believes that it is his right to wield technology in any way he sees fit. In other words, he believes that he is a law unto himself. Crake’s megalomaniacal inclinations are devastating in their scope and ultimately, result in his death. One could certainly argue that Crake was villainous in the manner with which he used his genius and the ways in which this affected the world.