User blog comment:Xilinoc/Ch. 675 - Blood for My Bone/@comment-1351982-20160526102945/@comment-1351982-20160526141236

I'm hardly the first person that's probably discovered that. It just further establishes the continuity in the storyline as opposed to a chapter cover. If anything the cover Xil pointed out, shows the possible symbolism of the mask being the lack of control. The Lust chapters are arguably the lowest point (other than the Lost Agent arc) Ichigo has come to as a character. He has completely lost control of the situation with Ulquiorra and he becomes a bigger threat to the lives of his friends than Ulquiorra at that point. In the SS arc, Zangetsu (Hollow Ichigo) can speak and has more human qualities, however Ichigo quickly regains control and has some awareness of what happened with Byakuya. That is not the case with his fight with Ulquiorra. Zangetsu has become a mindless beast and Ichigo has no control over his actions. In my opinion, the reason the hollow side/Zangetsu gradually became more animalistic is because Ichigo feared and resisted its power, which obviously was a recipe for inevitable disaster. Now that Ichigo has accepted both sides of his power, his Yin/Yang if you will, Ichigo has full control of his abilities, hence why the mask is gone.