Unlimited Transgression

[A human with portal capacity found.] [Intiating trial....] [Sending for the first world....] Where am I? Didn't I just walk out of the graduation hall? Why do I look like I am in medieval times? Why are the memories of my past so hazy? And what is this titanic wall towering over the city? *** First world: Attack on titan *** Basically, MC world hops between fictional worlds.