So, I found out Zekrom and Reshiram's origin, there origin is more than just yin and yang, and complete opposites of eachother. Here it is!
Zekrom and Reshiram were originally one Pokemon. That one dragon Pokemon made a new land together with the twin heroes, and people and Pokemon lived their days happily. But one day... The older of the heroes sought the truth, and the younger sought the ideal. A dividing struggle began to decide who was right....The single dragon that had walked with the twins was also split into two to support both.... A dark dragon that searched through the new, hopeful world for its ideal... Its name was Zekrom. And another, a light dragon that searched through the world of the past for the truth, its name was Reshiram. The two being equal entities from the very start only made the quarrel more violent. Whichever side won, the would end up absolutely exhausted....The twin heroes, too, could not find either to be right in their struggle... So the struggle was ended.... and yet, ... The heroes sons began to struggle again... so Reshiram and Zekrom used their lightning and flames to eradicate Unova in an instant.... But if people hadn,t been mistaken about how to get along with Pokemon, the world woulden't have been destroyed! So Reshiram and Zekrom did their best for everyone and made a new land!
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So, it looks like Zekrom searches for a hero that seeks ideal, and Reshiram searches for a hero that seeks truth. This is interesting! What do you think. Talk!
EDIT: This came from an English walkthrough of BW, from a utube user named Nightstar1994
Zekrom and Reshiram were originally one Pokemon. That one dragon Pokemon made a new land together with the twin heroes, and people and Pokemon lived their days happily. But one day... The older of the heroes sought the truth, and the younger sought the ideal. A dividing struggle began to decide who was right....The single dragon that had walked with the twins was also split into two to support both.... A dark dragon that searched through the new, hopeful world for its ideal... Its name was Zekrom. And another, a light dragon that searched through the world of the past for the truth, its name was Reshiram. The two being equal entities from the very start only made the quarrel more violent. Whichever side won, the would end up absolutely exhausted....The twin heroes, too, could not find either to be right in their struggle... So the struggle was ended.... and yet, ... The heroes sons began to struggle again... so Reshiram and Zekrom used their lightning and flames to eradicate Unova in an instant.... But if people hadn,t been mistaken about how to get along with Pokemon, the world woulden't have been destroyed! So Reshiram and Zekrom did their best for everyone and made a new land!
------------------------
So, it looks like Zekrom searches for a hero that seeks ideal, and Reshiram searches for a hero that seeks truth. This is interesting! What do you think. Talk!
EDIT: This came from an English walkthrough of BW, from a utube user named Nightstar1994