Yusei got up from his position after seeing his sensei arise. From the looks of it, the guy wasn't completely normal. "Hmph, this'll be interesting..." Yusei thought to himself. After taking in a deep breath in, he began. "I'll be sure to say this slowly so you'll understand. Smoke in itself is simply a visible form of carbon or other particles in the air. They're usually created from a burning substance. Smoke Ninjutsu a is a special form of ninjutsu in which the user takes control of preexisting smoke and utilizes it for a variety of techniques. Unlike elemental releases, Smoke Ninjutsu doesn't create smoke from the user's chakra. The smoke that is used is quite dangerous, being poisonous to even the user, which is why Gas Masks are regularly worn for users of this style. Smoke is generally created from Smoke Bombs, Wrist Launchers, or even from Fire. And that's it."
Yusei looked at his sensei with a relatively mundane look. "Did you manage to get all that? Or do I need to go slower?"