The blue ring reduces the damage inflicted by the enemy by half, and the red ring reduces damage to one quarter.
In The Legend of Zelda, Link can equip the Red Ring to take a quarter of the amount of damage he would normally and half the amount of damage with the Blue Ring equipped.[3] If Link obtains the Red Ring while having the Blue Ring equipped, it will replace the Blue Ring as an upgrade. In both the First Quest and Second Quest, it is found within the final Dungeon, Level-9. While Link has the Red Ring equipped, his tunic is red. Certain characters, items, and enemies share colors with Link's tunic and will appear red while Link has the Red Ring equipped, such as Princess Zelda's dress, the Arrow, and the whiskers of a Pols Voice.
In Hyrule Warriors, the Red Ring appears as Wizzro's second level Ring. An 8-Bit Red Ring also appears as Midna's star level Shackle. Throughout the game's Legend Mode, Wizzro uses the Red Ring form of his weapon. His Ring is a cursed artifact from which he manifests; it sucks the souls from its wearers, which are combined within the Ring to become Wizzro.[4]
↑The blue ring reduces the damage inflicted by the enemy by half, and the red ring reduces damage to one quarter. (The Legend of Zelda manual, pg. 23)
↑A cursed ring whose dark powers have been amplified by absorbing the essence of its owners through the ages. It condenses the souls of the deceased into a single, monstrous spirit. — N/A (Hyrule Warriors)