Nature
Captain Erbair had almost forgotten about Khan's background. The other wealthy recruits had a general understanding of mana that he lacked. He didn't even have the chance to learn about those topics in the academy since he had teleported to Nitis only a couple of weeks after Istorne's crisis.
Khan didn't even get the chance to learn about the first-level warriors and mages on Nitis since the Global Army had sent him to the alien academy. His knowledge had deep empty areas, but that didn't seem to hinder his growth.
"First-level warriors can't expand the mana normally anymore," Captain Erbair shortly explained. "They have to improve about half of their body at the same time, which obviously leads to slower growth. Did you reach that point?"
"I think I have," Khan admitted with the same tone used during the rest of the interrogation.