Yes. What I mentioned happened in the Season Zero arc equivalent. If you only watch the dub you never get to see this. There are a bunch of other things. Mokuba was actually a genuine threat twice. Once involving russian roulette with food, once with (once he lost the game they where playing) he DREW A GOD DAMN KNIFE AND TRIED TO SHANK OUR HERO.
Mokuba. Mokuba Kaiba. Yes, that one.