White is Yang which embodies Masculine traits.
Black is Yin which embodies Feminine traits.
Reshiram is naturalism personified full of explicit "Y" shapes and full of long jutting features to invoke flowing, unkempt hair/feathering including the famous not-penis making it one of the most Freudian designs since Palkia. Seriously, you lop of the arms and neck and you have a perfect phallus.
Zekrom on the contrary is much smoother, the humanoid torso allows her a hip to shoulder ratio that gives her a large but feminine frame [No, Resh doesn't. It's an animalistic build. He's basically a stout bird.] and feminine features like massive hips, a midriff and breastplate [the latter of which in some mediums can even come off as a bust] and a much more conservative, modest look in contrast to her other half.
tl;Dr They follow Tao pretty fucking well. And the games outright said it in the Japanese version.
https://www.youtube.com/watch?v=GKBZXVy35Kchttps://www.youtube.com/watch?v=JtNEzM486NEResh is FABIO, Zek is gym brat.
