…what is actually the point of this constellation? Is anyone using it, and if so, why?
The way I see it, the ‘speed’ aspect of it (slow resist, 35% movespeed) seems largely irrelevant because such a boatload of movement speed is eclipsed by a low movespeed cap and slow resist isn’t as hard or as necessary to acquire as other CC resists. The Armor and Retaliation values are pretty negligible (8% armor is OK, 50 Armor is basically nothing) and the proc doesn’t even have 100% uptime.
I use it here
http://www.grimdawn.com/forums/showthread.php?t=49867
Reasons
-Flat nodes are valuable
-The final skill is a big bonus to Pierce retaliation builds
-reflection node is important
It’s a pretty offensive constellation from retaliation point of view and imo the best one for retaliation builds
Heh, I kinda ignored it since reflection is a joke of a stat. 
400% reflection is significant imo
But i see what you mean 
Anyways this constellation isn’t useful for non-retaliation builds but for retaliation it’s pretty good
I have a bleeding / lightning Warder, who also has a significant amount of retaliation damage, and I was about to say Messenger of War was the only constallation with an aura skill, which I meet the requirements for and fits my build. But there are also Chariot of the Dead and Ghoul and both, but especially Chariot, look much more appealing to me. And I was so happy, to include Messenger to this build. :undecided:
I just made a retaliation warder and use it. It gives great stats and the proc is ok. I get up to 200k hits atm without devotions maxed and still not bis and this devotion helps a lot.
My observation is that movement speed and slow resistance do not synergies with a retaliation build? Or? Movement speed I would think of a kiting build. Sure anyone would want movement but it is in place (opportunity cost) of something else that would fit more with retaliation.
I like moving fast and retaliation builds aren’t invincible contrary to popular belief. Not everything is a melee attack in the game and in some cases (Crucible) you need to GTFO
I continued to play my Unholy Covenant pet build and realised that I picked Messenger of War, too. I think I chose it mostly for the affinity points it provides, but my skills also include some sources of retaliation damage, so this looks like a decent synergy.
My impression was that you’re not doing DPS when you’re moving, hence the retaliation. Note that retaliation can actually proc several item effects that usually only proc on attack.