Chopper deduces that Oars originally died from frostbite 500 years ago in the Land of Ice.
Moria also uses a useful defensive feature of his Shadow-Shadow Fruit powers to instantly switch places with his shadow, Doppelman , allowing him to evade attacks—such as when he rendered Nico Robin's Clutch attack useless by swapping locations with his shadow. Episode Overview One Piece Episode 371
"Moria Destroys the Straw Hats One After Another!" (or "My Name is Moria!") Chopper deduces that Oars originally died from frostbite