How does Harmony work?

[koros]

I don't play a druid or ranger here, but unless it's different than live harmony has no resist check and can't be resisted.

Mobs have both a frenzy and a reaction radius. Frenzy radius is the range they'll aggro, and reaction is the radius they'll assist. Harmony reduces these to 15 for both. If you walk within 15 units of otherwise aggro mob who's harmonied they will attack. If that mob is within 15 units of another mob that it shares group aggro mechanics with, the other mob will assist. This limits harmony for closely packed mobs, but in many cases 15 is small enough that you can single pull them, especially if you make sure the mob you're pulling takes the path that keeps them the farthest away from other mobs.