Marc is retiring... not sure the best way to deal with that IC...
I have an idea for that, which should work out fine.
Holdamir (or was it the other one?) returns with info from Baztgirn (Torgthen's town)... it's under attack. But he also told the council his tale of finding the construct, and the dwarves know of another site, which might be similar to the one the MARC came from, which is quite close by. So the MARC flies off to Baztgirn to find more information about his origins, and promises to help the town against the attackers in exchange.
And to stop Torgthen from rushing home: The town's authorities have specifically requested he look for the source of the problem, rather than help with the symptoms. They can hold out.
Work out for everyone? We can do it IC in another bit of campfire talk, unfortunately to take place after this fight, or else the Hound won't be back. Now the other question is whether you want to immediately head for the demon camp, or whether you will stick around to lick your wounds a bit longer.
So you'll just have to play the MARC until he leaves, which could be soon - or I can NPC him if you're really that sick of him.