How to create this ultimate life drain??

[R1DL3R]

I try to create life drain (onlu GUI)
with editing the efects of power starfall but just efects then i create triger
"if unit is atacked by spell casted by hero of spell starfall activate trigger XX"
"every 1 second set life of atacked unit 100%-20points"
"pick castin unit and set hero llife bonus +15 points every 1 second"
"if ability stops turn off trigger"
i dont want to copy trigger so i make like this but if someone had any question just ask so can someone help me with GUI efects
i want to select when i activate spell i send to all unit in region of spell
that lighting (life drain efect) its from the sky and then one its to casting hero to his head ant its give bonus to his life point by 15 for every unit in radius.So ability that select unit in radius xxx drain from them life by 20 hitpoints and give to casting hero +15 hitpoints.So i dont want trigger
of this spell just answer how to create this lithings...???thath falls from sky..
not direct...can someone help me???

 

[Sephalo]

Show me which trigger you're using now.

Some things I don't like are: Set unit hp to Current hp of unit - 'damage'.
you should do a Pick every unit in units within 500 (per example) of Casting Unit Matching owner of matching unit is an enemy of owner of Casting unit and do actions:
Order casting unit to damage picked unit for 25 attack type spells, damage type normal...

But first show your trigger, I might edit it a bit.