Suppose I have Book of Hozai and Obedience of Noah in hand. I make a rescue attempt with Benjamin, he's blocked, and then I play Book of Hozai. I draw Huge Egyptian and two other cards. Then I play Obedience of Noah to choose Huge Egyptian as the new blocker. My opponent then plays Mask of Fear.
Now Book of Hozai's draw is negated. The character that I chose to block - Huge Egyptian - was drawn via Book of Hozai. Does Huge Egyptian go back on top of my deck? I would rule no, since CtB abilities are CBI, and it sticks, but based on the Evil Armor thread, I guess it would be indirectly negated and the first blocking EC comes back into battle?
Relevant abilities:
Book of Hozai: Holder may draw three cards and play the next enhancement. During discard phase, holder may return any cards from hand to top of draw pile.
Obedience of Noah: Holder may choose the Evil Character that his opponent uses to block his rescue attempt.
Mask of Fear: All special abilities on Character cards and enhancement cards except this one are interrupted and prevented. Battle is determined by the numbers.