"He’s a thug, isn’t he?" asked the girl.
"No, not a thug. A Thuggee," said the older priest.
"What’s the difference?"
"A thug is common parlance for a common criminal who uses their muscles to rob people. Or someone who acts as hired muscle for some criminal enterprise. The word itself has been shortened from something much older - Thuggee. Thuggee are a murderous cult, dedicated to an old forgotten goddess of death and - I shall choose my words carefully here - marital relations external to the formality of wedlock.
"They practice forbidden magicks, using such dark arts to unnaturally twist and enhance their bodies - or to cause pain and suffering upon others. They are liars and deceivers, and only care about their own pleasure and power."
The girl interrupted the story with a question,
"I heard forbidden magic would stain the soul. Do they not fear the afterlife? Do they not fear Hell?"
"He is a goblin, my child. Goblins are cursed fae. The Fae do not have souls like you and I, destined to be reborn in a new body as the New God intends. No, the fae have souls that are bound to their bodies. And though they are ageless, they can still be killed. When they do die, their souls die as well, rotting away as the flesh rots on the soil."
"But goblins are cursed fae - they have been stripped of their immortality. They have the worst of both worlds - they die young, rarely living more than a handful of decades, and their souls die with them when they pass. They do not transcend into the underworld to be reborn. No, my child, this creature shall never face the fires of Hell, he shall never suffer the consequences of his actions in the afterlife. This is his one and only life. That’s what makes him so dangerous. Be wary around him."
Fingas isn't a nice person - unless you are a goblin. He is actually rather kind and willing to help out any fellow goblin. But years of torment at the hands of humans and other people have left him sour and bitter, with a thirst for revenge against those who have treated him and his kind poorly. This is why he has spent time studying the forbidden magics - in hopes of laughing at the suffering of the people who have trampled upon his kind.
So why does he care about the Maidens of the Moon? Why does he give a rat's ass about them? Short story is, he doesn’t.
The Maidens were complete cunts. They looked down upon him, both literally and figuratively. They were secretive about their magic and wouldn’t tell him shit. They hated dark magic, which forced him to be extra secretive about it himself. But they accepted goblins. They accepted his people. Some of them were goblins themselves and occasionally he was able to pry some of their secrets from them - not the priestesses, mind you, but some of the other servants. Or at least the goblins in their service.
Fingas had connections and he was able to get shit done; unsavory shit - and sometimes some of their goblins would ask him for help. That’s mostly how he pried their secrets from them; he would trade information for services rendered. A goblin was being harassed? He’d curse the shitheel and send them packing. Once there was this human shitstain that beat the crap out of some goblin girls. Stole everything they had. When Fingas got to him, he laid out one of his best curses and turned him into a goblin girl - "Let’s see how you like it being one of us. Let’s see how far you will make it, treated like shite by your own kind, living as the very thing you despise." Fingas got shit done.
Well, now that the Maidens have all disappeared, the goblins who worked for them were all in a tissy. They came to him, knowing that he gets shit done. They begged him. They pleaded with him. They offered promises and favors and, well, it’s a good thing they weren’t Maidens because they sure aren’t now.
And now? Now Fingas is on a mission to find the Maidens. He doesn’t care about their fate, but he does cares about his goblins. His goblins care. He will do it for them.