BlazBlue vs Kingdom Hearts

Connection:

Both are female video game characters who are considered Replicas (Celica of the original Celica, and Xion of Sora) constructed as weapons to the ulterior motives of a manipulator albeit in different ways (Kokonoe planned to use Celica to put a permanent end to Terumi and the Imperator, whereas Xemnas sought to use Xion to extract hearts to build his own Kingdom Hearts)

From being destiny's puppets consigned to their fates, and seen by many as not even having the right to exist, they struggle on to do good where they can; especially for the people they love the most (Ragna the Bloodedge and Roxas respectively)