This thread explains in general terms when elemental types matter with regard to damage calculations. For Boomer’s special specifically, Holy defense increases by 94% (just shy of double), so you would expect to see damage from Holy sources reduced by about half. This damage reduction applies to:
- Yellow tile damage
- Attacks from minions protecting Holy heroes.
- Normal attacks from AI-controlled Holy enemies/heroes/titans (even though these attacks are non-elemental)
- Special attack damage from both player-controlled and AI-controlled Holy enemies/heroes/titans (even though these attacks are non-elemental)