Similarities and contrasts on the cover of volume 11
The cover of volume 11 featuring Mutsuki has some similarities with another Touka color illustration launched by Ishida around the same time:
This far from being for chance is done with premeditation. If we look at the circular forms located behind Mutsuki, we will see that there are written some letters that form the word "aktor"
Aktor is an Indonesian word that in english means actor.
Mutsuki just like Touka feels a deep love for Sasaki, which being aware of the type of relationship that they both share leads him to suffer an intense jealousy towards her. This is reflected in this illustration, in which we can see how Mutsuki tries to act as if he was her:
Mutsuki tries to be someone who he isn't, imitates both her body posture and her facial expression, covering the same eye as her, placing a crown on his head (clearly alluding to the fact that Touka having married with the king acquires the queen status on a symbolic way), arriving so far as to change the color of his own skin
or putting a "wing" where is frequently represented Touka's kagune
This wing-shaped figure was used before in the cover of volume 3 (from Tokyo Ghoul) to reflect that Hinami's kagune had in its upper part the form of butterfly wings:
and also in the illustration of Tokyo Ghoul Past novel to reflect that the kagune of Touka had the shape of a wing:
However, as we know, Mutsuki doesn't have a kagune whose shape has the form of a wing, that's why it's represented by a black liquid emerging from it, indicating that it has been put there forcedly.
Despite Mutsuki's efforts to resemble Touka, some differences still remain. As we can observe in the diferent illustrations, despite tilting their head in the same way and having the same look, they do it in opposite directions; while Touka's smile is itchy, Mutsuki's smile seems to be malevosy; even though he wears the same clothes as her in this illustration:
We continue visualizing them from different perspectives, while we see Touka from her back, to Mutsuki we visualize him from the front.
Meaning that for him is impossible to totally be her.
These differences that are contrasted in the two illustrations with Mutsuki's one, can have in turn the purpose to make us compare both forms of loving Kaneki, because despite sharing the same feelings towards him, Touka would sacrifice her happiness for Kaneki, meanwhile Mutsuki for the sake to make him return to the Chateau, would sacrifice Kaneki's happiness for his.
Thus the Mutsuki cover of volume 11 was made in such a way that it could be contrasted and compared with both Touka's colour illustrations.