Verified for patch 16.8.1

Reactive Armor

Taking damage from enemies grants 4 bonus Armor and Magic Resistances, up to 50.

Source

Effects

MaxReactiveArmorAndMR
50
ReactiveArmorAndMR
4

Reactive Armor enables

  • Armor On the Menu

    The physical-defense stat that reduces incoming AD damage. Tank items, Bastion-style traits, and ability bodies that read "Gain X Armor" or "Your team gains X Armor" all land here, alongside the handful of cards that scale a bonus off the unit's Armor value.