It depends but the difference is negligible vs mobs with 0 magic resistance that it wont save you 1 cast of hammer.
%magic damage stacks multiplicatively with -%res.
Vs0% magic resistance
-30% magic res and 15% md yields damage boost= 49.5%
-45 % magic res on 0 resistance target = 45% boost
If you play dota2, this is the reason why getting evasion on a hero with already high hp and armor is a higher EHP yield
Vs broken immunes and mobs with MR like mephisto, -% res will outperform.
So def go for -45 magic. magic opalvein seems very niche bec it doesnt offer pve utility for hdin ( with 2x sling you get 40% magic find ). Although 2x opalvein could work with max mana on kill + 6 on hellwarden to replace the need of insight (I'd still suppose this is very clunky).
This post was edited by Hajun123 on May 17 2026 03:50am