Roman's sudden question caught Klaus off guard; he wasn't expecting it out of nowhere, and the surprise nearly broke his usual poker face. Although he tried to maintain a calm exterior, his thoughts were racing like a tornado, moving at a speed only a mage could handle.
'How did he know?' Klaus asked himself.
'No, he can't know. Even Greed can't tell how I use magic. So how does he know I can use magic? Was it during the first test? No, he couldn't possibly see through the fog created by the aequalis array.'
'Ah! I know!'
Klaus finally realized the mistake he had made that let Roman discover his secret.
'He could see through the mana wall I generated to cloak myself while using magic.' Having realized how Roman found out, Klaus now needed to explain himself.