Damage Reduction is capped at 0.8 (magic damage is reduced by 80 %), which can be achieved at 152 HV. (Mana Reflector Mastered) Magic Strike = damage from Magic Skills (damage you would receive without Mana Reflector). Reduced Damage = damage you would receive with Mana Reflector. Reflected Damage = damage reflected back to Attacker. Reflected Damage is magic type damage. It is reduced by Attacker's Magic Resistance but ignores Attacker's MD. Mana Reflector can be stacked with Sumo Suit to increase magic damage reduction. (Reflected Damage remains the same. Casting order doesnt matter in rTO) Example: A monster normally does 1,000 magic damage (Magic Strike) to you.
With 80 % Damage Reduction from Mana Reflector, the monster would do 200 damage. Reduced Damage = Magic Strike * (1 - Mana Reflector Damage Reduction) = 1,000 * (1 - 0.8) = 200
With 80 % Damage Reduction from Mana Reflector and 50 % Damage Reduction from Sumo Suit, the monster would do 100 damage. Reduced Damage = Magic Strike * (1 - Mana Reflector Damage Reduction) * (1 - Sumo Suit Damage Reduction) = 1,000 * (1 - 0.8) * (1 - 0.5) = 100
Reflected Damage would be 800 in both cases. Formula OK