Is it maybe Aghimin or however you spell his name, Ganon's alter ego in LttP?
And Myriad, FirveIce is just good at hiding stuff.
Wait, is it those flying Lizardalfs in TP? In the City in the Sky?
I'll go. I haven't had a chance yet. This might be easy, though.
Subject: OoT
As different as night and day,
Yet we are as alike as brothers.
We are as identical as twins,
Yet as opposite as sun and moon.
What are we?