Haven't played MP yet, nobody on my friend list, and all my Cabal applications sofar have been ignored, even though I even wrote a ingame mail to their respective leaders... and since I am not one bit interested in PvP, that's pretty much all she wrote in terms of MP for me for now.

That said, from a technical standpoint, I can't really imagine why the very same skill in the very same game running the very same engine and the very same code should behave differently itself -- what I do however suspect much more, given the comments all around re: bad netcode/online performance and stability, would be that this might just be a symptom of the MP sessions being not very stable right now.

Could be wrong of course, but it would be very strange otherwise... but either way, it is, according to its tooltip, actually intended that only one pillar per enemy is spawned, no matter how long you hold down that button for, and additionally, all those enemies need to be rather close to you too and stay within that range while casting for it to work at all.

The latter is actually why I myself at first thought this skill to be completely bugged, as nothing happened while all other skills worked great -- only noticed at second glance that, at my regular range, this skill's icon was actually still greyed out due to being out of range.

Extermination only spawns pillars if you have enemies in range, and it only spawns one pillar per enemy -- the tooltip says as much too and that works perfectly fine. As long as you have enemies enough in range, holding down the button spawns additional pillars and that does raise warp heat extremely, plus damage you instantly regardless of actual heat level, as advertised.

Extermination is skill bugged nonetheless, as the tooltip also claims that these pillars of fire would track their targets, which they do not, they remain stationary once spawned; I have already created a listing for the Bug Tracker:
http://old.neocoregames.com/mantisbt/view.php?id=4726

Also buff that adds Dodge to range attacks ignores 10HP/Sec psy power rune. So you buff it, but +10HP rune doesn't work with it.