MoM: Heal for 15% ATTACK DAMAGE dealt

When mask of madness says it heals for 15% of attack damage, then that is what it should do...

And I'm pretty sure it's not stealing life on magic attack damage dealt

I just had 5 javelins and 1 mask of madness and every time I performed a triple proc of 100 magic damage I did not see any increase of life stolen

That's correct. It has to do with how the damage instances are calculated. Javelin is a magic damage instance that's calculated separately from the attack damage instance of a hero, so life steal doesn't proc off of it.

That's pretty inconsistent though, since something like Void's Time Lock is magic damage, but IS calculated as part of the attack damage instance, and therefore procs life steal. Maybe changing the way Javelin works so that you can lifesteal from it would... buff... something?

It's probably fine as is, but that's be interesting. Lifesteal on Maelstrom woo.