“… it ain’t worth it.”
Any idea if something other than a power grab was on the table for Gallywix? I know he has a history of cycling through “I’m alone in the world, I don’t need anyone” and “wish someone would love me”. Wonder if Xal played into that somehow.
I do wonder if we will find out Gallywix was doing something sort of good in his own evil way.
Maybe Xalatath offered him to keep Undermine has his own fiefdom in her service - sparing it from the total destruction that others would surely face.
One thing that sparked my curiosity is during the boss fight, Gallywix says:
“you chumps owe me”
As if he did something for us that we don’t know about and he doesn’t want to say.
probably not, the time to build up gallies motivations was during the campaign and they didn’t do it.
I kinda wonder if Gallywix just recognized a fellow scammer when he saw one and was holding onto the repaired Dark Heart instead of handing it over right away because he figured it would give him leverage and keep Xal’atath from just having him disposed of once she had what she wanted. That’s kind of her M.O.
Theoretically, as long as he still had it he could potentially demand whatever she’d promised and threaten to hand it over to us instead if she reneged on her part of their deal.
His “you chumps owe me” line seems to be keyed to adds spawning in during the fight, so I think that’s just him calling them. A lot of the mobs and other bosses in the raid who aren’t explicitly Darkfuse are supposed to be goblins who personally owed Gallywix, as he called in all of his debts to protect him after losing his leverage on the other cartels cost him most of the manpower he had in Undermine.
I swear the game said this explicitly somewhere. Did it not and I just imagined that was the case because it seemed clear?
I only remember she directed Gallywix to the Black Blood. A similar if same deal to the Nerubians. 
I do not recall it being said explicitly, but I also just assumed a scammer knows a scammer, and Gallywix was holding back until he had an exit strategy of his own planned, and he thought the Ethereals coming for the Heart was Xal’atath calling his bluff.
Maybe it does make it clear somewhere!
I remember the scene when he realized it wasn’t the case, and how emotional they both were. Xal lost her cool and became enraged, while Gallywix looked genuinely hurt when she abandoned him. He did say “we” can fix this to try and appeal to Xal. As opposed to “I” can fix this. Meaning he might have had some delusions about the situation.
“Cartels divided… can not survive… what is to come.”
I think it’s supposed to be his hobgoblins. Funny enough, there’s no goblins that show up to aid Gallywix in his fight, it’s all mechanicals and oafs. Every true goblin either died or abandoned him (like that one idiot with the mice.)