Celtic Heroes

I have been using howling wind on my druid recently and find it very useful on some bosses. When you have a 35/35 howling wind, barely any of the mobs manage to melee hit you. Including the OW bosses.

But I noticed that the howling wind doesnt work on red bosses for some reason... Do they have extremely high attack? Or are they simply immune to howling wind?

Probably their attack is super high like you said?