Spell Help - Life drain - Permenantly increases hp?

Im trying to make a life drain varient.
There are 2 things

1
A unit casts life drain, for each point drained it also adds to maximum hp of that unit.

2
A dummy ability is used and when casts, creates multiple drains lifes.

e.g. Casting unit gains 5 drain lifes from nearby enemy units, permenentanly adding hp to him.
(Does not permenentaly reduce hp from targeted units).

Unit will be paused/channeling dummy spell whilst casting so no movement is possible.

Hopefully someone could put me on the right track

I was thinking making a trigger.
Every 1 second, setting hp?

thx

SetUnitMaxState System

This is what you'll probably want to use for the first part.

For the second part, setting up a periodic trigger that drains life from the targets and then calls the SetUnitMaxLife function to increase the caster's life isn't too hard. Also just create a lightning effect and caster target effects on the appropriate units.

Edit: Nevermind, got confused.. Instead of using the SetUnitMaxState, you could use the BonusMod after what suits you the best.

- Soultaker

thx guys, I manage dto get it working :-)