Main Article: Buildings
- All buildings, except for tier 1 towers have this ability (although tier 1 towers have the 60% attack damage reduction against illusions).
- Tier 2 towers have a search radius of 900 centered on them, each of them independent from each other.
- The base buildings depend on the Ancient's search radius of 4000 centered on it. This means they all lose the protection together.
- The unit detection is aura-based. If an enemy lane creep gets within the search radius of the tower/ancient the protection is lost.
- The aura's effect lingers for 0.5 seconds, so the total reactivation delay is effectively 15.5 seconds.
- Applies generic incoming damage reduction on the building. Stacks additively with other sources of generic incoming damage manipulation.
- The illusion attack damage reduction does not require backdoor protection to be active and works on all buildings, including tier 1 towers.
- Applies unique incoming damage reduction to illusion attack damage. Stacks multiplicatively with sources of generic incoming damage reduction, like the active aspect of backdoor protection.
- If a building is protected, the building takes 90% less attack damage from illusions. Their spell damage is only reduced by 75%.
- If a backdoor-protected building is damaged by an enemy, it immediately starts healing back.
- Heals 9 health in 0.1 second intervals, which translates to 90 health per second.
- This means, it is possible to destroy protected buildings by dealing more than 90 damage per second (after reductions).
- Only heals back damage dealt by enemy units. Damaged dealt by allies is not healed back.
- Treats creep-heroes as creeps, except for the , which is treated as a hero.
- Treats as a creep.
- If a non-hero unit has piercing attack, it is only affected by the attack damage reduction against piercing attacks, and not by the reduction against non-hero units.