Hp requirement for ability

[kokon]

If ability requires mana then it is shown in the tooltip with a light-blue text and mana icon.
Can I somehow make a requirement so ability requires hp?
Can I also display HP icon?

 

[Dr Super Good]

I do not think this is directly possible in Warcraft III. In StarCraft II it is trivial but Warcraft III casting costs are quite hard coded.

I think the best you can do is use triggers to enforce the health requirement and then try to use a custom tooltip, or even custom UI, to try and indicate to the player that the ability has a health cost.