"Cyber Dragon" + "Cyber Dragon" + "Cyber Dragon" A Fusion Summon of this card can only be done with the above Fusion Material Monsters. If this card attacks a Defense Position monster, inflict piercing battle damage to your opponent.
It depends what you consider Seto Kaiba's role in the original series to be. If it's just the main protagonist's main rival, no, that's definitely Chazz. But, like Kaiba, Zane (and a few other characters like Aster) he's a strong duelist that's been both an ally and antagonist of the main character.
Personally, I don't get why people try and label people as cross-series counterparts, but eh.
Well, both Zane and Seto have a younger brother, an ace LIGHT "Dragon" monster, a fusion monster which is made by fusing 3 copies of their ace card and a serious behavior. Not to mention that both get obsessed with winning after being defeated (and humiliated) for the first time (on screen).