Hidden Attack

"Internal Energy!" It said out loud as I got over over shock of me repelling its hidden attack. "So, you are practicing an art; no wonder you are so powerful for your stage," It said, looking at me with far greater seriousness than before.

It had got that one right; I am quite powerful for my stage, and the funniest thing is, it has no idea about my true level. If it comes to know about it, then a simple shock would not be the reaction it would have.

"Yes, I have an art, and you should show me something good to worth my time, or I will just kill you," I said as I swung my sword relaxedly. 

This time it did not laugh at my words and looked at me intently before letting out a sigh. 

"I was keeping this hidden for the really strong enemy, but now it seemed like I will have to use it to kill you," It said with a hint of slight unwillingness before a change in its aura began, and it is not explosive but smooth.