Complex sentence: In "Ocarina of Time" the Master Sword dosen't work the best on a ReDead due to the fact ReDeads are made of dark magic making it to where the Biggron's Sword is the best weapon against a ReDead.
Split into simpler sentences: In "Ocarina of Time" the Master Sword doesn't work best on a ReDead due to the fact that ReDeads are made of dark magic. Thus, the Biggoron's Sword is the best weapon against a ReDead.