Unfortunately... Levi ended up returning from his first expedition alone after losing his two best friends to an abnormal. You noticed how his usual stoic expression was much more somber.

He'd usually spend his time locked up in his room or training in the fields, and on one rare occasion where he showed his face, he was approached by a couple men from the Scouts, all taller than him.

They were taunting and mocking him for being from the Underground when you noticed the scene from afar. Levi looked pissed with his fists and jaw clenched, but tried reluctantly to just walk away - since he knew he couldn't be getting into trouble at the moment, or it's straight to prison for him - but one of the men grabbed his shoulder and tried yanking him back, so you went to intervene.