(This is a review of both Superior and Superior Cross)
In the beginning, I liked Superior. It was cute in that it was like an RPG with a party that included a hero, the hero's right-hand swordsman, and a mage (and later, an assassin-type) all out to destroy the Maou. And I liked how it handled Shiela's fear of the inevitable day when the hero realizes that she's the enemy, and how desperate she is to keep her identity secret. I looked forward to how Exa and the others would react upon learning that Shiela was the Big Bad they were out to kill.
But when Exa finally found out... let's just say I was not impressed.
What happened to all that angsting you did, and your final conviction to believe in the Shiela that you know & love? You just suddenly throw all of this away in your rage, even though Shiela told the truth while apologizing & in tears, moments before she went and tried to sacrifice her life to save yours? :/ Ok, I guess it's understandable considering you've hated the Maou for a long time (she did kill your parents and decimated your entire hometown, not to mention half the world's population), and you feel betrayed and stuff, but then you suddenly turn around and are not mad anymore? Wait what???
I also found the ending rushed, and didn't make a whole lot of sense (or maybe that was just the scanlation).
I don't understand why the mangaka had to create this Original Maou character. There's Copy and Third already, why make Shiela a clone too? >>; It would have been better if the author had stuck with Shiela being the original and just prolonged the Exa vs. Shiela fight, delving more into their emotions, Exa especially. The scenes would have been more heart-wrenching, and the eventual acceptance, forgiveness, and 'I still love you' moment would have been more awwww-inducing.
All in all, it started out pretty good, but devolved into a rushed, mediocre manga that left much to be desired.