Will of Fire, and Explosive Flames (Please Vote Monthly!!)

What exactly is the Will of Fire? And why do you want to become Hokage? With the smile of a kindly old man, Hiruzen Sarutobi asked, "If one of you answers correctly, I'll let you return to your seats and listen to the lesson." Wait, weren't those two questions? Hearing the extra question tacked on at the end, Kushina could not help complaining inwardly. Such a theoretical question had to have a standard answer. As a transfer student from elsewhere, it really put her in a difficult spot.