“By making such a sacrifice to demonkind, you'll be able to sever any last remnants of your own humanity.” Ubik, Vol. 3 Ch. 2

The real meaning of the ritual is less about the physical act of sacrifice, and more about the symbolic sacrifice of your own humanity. It serves to sever mortal ties with the human race. By the age-old logic of sacrifice, the more you have to give, the more you gain in return. In the past, loved ones were sacrificed to become minions like Zodd or Wyald. No small feat! Yet consider how much greater Griffith's sacrifice must have been if it had the power to turn him into a god! Yet a question still remains: was this the result of the intensity of his caring? or simply the result of the special type of Behelit he had? I would say both. The type of Behelit he had was the direct result of his capacity for love, which he would then be driven to sacrifice when cornered so cruelly by fate.

“A fissure in your heart will open up into which Evil will surge.” Conrad, Vol. 3 Ch. 2

Of course, in order to sacrifice your humanity, you must first have it, and once you lose it, you change. You become an empty vessel which, according to Conrad, gets filled with "Evil." But what is this Evil?

“All their deaths are piercing through me! I wished for it. I killed them. It's strange... I don't feel anything.” Griffith, Vol. 13 Ch. 3

Yeah, pay no attention to the text in the picture, it's all wrong. Griffith took ownership of his decision to sacrifice his comrades, yet as he sensed their deaths fueling his transformation, he felt numb. He had sacrificed the last remnants of his tears along with them. Unable to contain his pain, his heart had frozen over. Femto would become the sterile, callous personification of not his dream, but his ambition. And it was, indeed, what he wished for: a form free of mortal weaknesses like love and pain that could distract him from his goal. His soul body was disintegrating, and he was falling deeper and deeper into the darkness.