[Spell System] Health as Mana Cost

[Deep Sea Kraken]

I saw something like this ToB (Tides of Blood), where one of the hero's spells cost health to use, but if your health is below the cost you cannot cast the spell.

I know you could do that with techtree requirements, but the one in Tides of Blood (at least as far as I remember), did not use that, the maker had it so the spells had the health cost like spells have mana cost.

Any idea how to do this?

 

[Cookiemaster]

Make a trigger that lowers the HP by xx (spell cost) when Triggering unit casts the specific ability.

You can also add a condition that Triggering unit needs a certain amount of health first. (To prevent it from suiciding...)

 

[Deep Sea Kraken]

I know, but the way they made it, it was literaly the mana cost was replaced with health cost.

You know how spell icons turn blue/purple when you dont have enough mana? That was I mean, except with health.

 

[Elven_God]

I think they have do that the spell need mana for casting and when they cast it remove life and set mana to life of unit.