"You will be by the time I'm done with you," Piccolo said with all confidence in the matter. Though now he was curious. "What is your specialty? Firearms? Something else?"

Armies usually had guns, right? Unless it was a world without those. So maybe swords instead? He could get Trunks to spar with a sword. Well, hell, he could spar with him with a sword but Piccolo wouldn't be wielding one so he didn't know how that would make the guy feel. Anyway, it could be neither of those. He didn't know much about armies these days anyway.