Subseries warning: This article or section contains information on a subseries within the Legend of Zelda series and should be considered part of its own separate canon.
Ruto's Scales are the shed Zora Scales of Princess Ruto and her Gold Material drop from Hyrule Warriors.
In Hyrule Warriors Legends, they are also the Gold Material drop of Medli, likely intended to be a reference to the fact that the Rito evolved from the Zora.
Subseries warning: Subseries information ends here.