Pandora Hearts, Crimson-Shell Recommendations
Both are from the same mangaka and they have a similar setting, as well as characters who look similar.
Both of them are from Jun Mochizuki, so there are a lot of similarities everywhere. Main character, Claudia, looks like a younger version of Alice (main character from PH) and not only this, chara design is generally very similar! This manga is like a little sister for Pandora Hearts... And has a lot of bishonens and very good plot too!
Crimson Shell was a sort of early incarnation of Jun Mochizuki's later work, Pandora Hearts. Both have her signature drawing style, and several of the character designs are similar. Both have similar settings and themes: An organization was instituted to fight against monsters, there is a girl who is one of those monsters but is different and more powerful. She has been forced to join the organization. A crucial part of the story is her trust in an older man, and how it seems that trust is betrayed. Lots of intrigue and magic. CS is only one volume, though.