What's the Name of That Book??? discussion

Looking for a fantasy trilogy: heroine is prophesied and introduced as a little girl after her parents are killed; only her brother survives and later joins the villain. The heroine has a mystical glowing hand (shown early) and a special sword. The villain finds a gemstone deep in the mountain — called something like “blood of the earth” / heartstone / hearthstone/ebbing/erbing stone — which is the source of his power; he reshapes and bends victims through torture, and once helped someone become fertile. There are ogres/trolls (their leader’s name sounded like “Towtruck”), elves that live in flying castles / sky-planes, and a character who speaks in a singsong voice. No dragons. Any idea what this is?

I listend to this audio book so the names and spelling could be wrong, but i certainly remember one of the characters descibed as speaking in a sing song voice, being an else, living in flying castles and using flying boats. The book was a trilogy. The heroine was discovered early on when her palm started glowing; she connected with a spirit to learn about her abilities. She was a human. The book featured other mystical races. She and her brother were the only survivors of her family.

I'm pretty sure this is the Banned and Banished series. There are actually 5 books. Wit'ch Fire is the first.

Girl's hand doesn't really glow, but it does turn really red. She and her brother are the only survivors when her home is attacked. She eventually teams up with a one-armed 'hero', and together they fight off the darkness.

Her brother eventually joins with a dark wizard to get his youth back.

The troll's name is Tol’chuk, which could sound a lot like Towtruck in an audible book.