How to make same passive like this...?

[IRoILaurentiu]

Enables Bloodseeker to sense enemy Heroes whose health is below a certain percentage wherever they are, giving him True Sight on that unit, increased movement speed. Bonuses stack per Hero.

 

[david200923]

Make a loop (ex every 0.5 seconds) picking every enemy hero and check if their hp is less than that certain percentage, if so then make a dummy for bloodseeker owner and give it faerie fire and order the dummy to cast it on the picked enemy hero, and give bloodseeker unholy aura with multiple levels and level it up/down as needed.

 

[Light]

Bear in mind that unlike Bloodseeker in DotA 2, movespeed is constrained to 522 in Warcraft 3.

 

[IRoILaurentiu]

Give me a screenshot? To learn about this spell and created.