The series I remember is about a young female lead. She is in a world where human trafficking is common. The rich and powerful are able to take another person's attributes through the use of a Blood Ore or Blood Metal. The female protagonist doesn't join the practice, but rather eats the brains of large insectoid creatures to gain supernatural abilities. The human inhabitants are fighting each other, ignoring the looming threat of giant deep earth dwelling insectoids.
Probably the Runelords series by David Farland.
The rich and powerful are able to take another person's attributes through the use of a Blood Ore or Blood Metal.
The main magical system of the series relies on a system of attributes which are inherent to every living creature. These attributes are transferable to and from both man and animal, so brawn from a dog can be transferred to a man. Once an individual gives an attribute to another, the giver loses that particular attribute until the death of the recipient. Each person can only give one endowment in their lifetime. Endowments include brawn (physical strength), grace (physical dexterity), wit (memory and clearness of thought), metabolism (speed at which the body's processes operate), glamor, voice, stamina, sight, hearing, smell, touch, taste, talent, will, bloodlust, and pain. [...] Endowments are transferred with special tools called forcibles. A forcible is cast of a rare material called blood metal into the rune corresponding to the endowment to be transferred.
The human inhabitants are fighting each other, ignoring the looming threat of giant deep earth dwelling insectoids.
Reavers are a massive species of subterranean creatures which bear no resemblance to any surface dwelling creature. Reavers are somewhat like insects, communicating through scents and having various "castes" which perform different functions within their "hives", though they do not have a collective intelligence. They are unchallenged masters of the Underworld.
The only part which I can't find a fit for is the female protagonist. From Wikipedia it seems that both the Earth King series (first four books) and the Scions of the Earth series (fifth to eighth books) have main protagonists who are male: Gaborn and Fallion respectively.