The Starblood Tithe (Bloodthorn Court) by Marine Stompsword

Every year, twelve mortals are chosen for the Blood Tithe. They are called volunteers. They are called necessary. They are called the price of survival. Wren of Greymoor knows better than to believe pretty names for ugly things. When her sister’s name is drawn, Wren does what she has always done: she steps between Liora and the knife. But the fae realm beyond the Veil is not the story mortals were taught to fear. It is worse. The Thornbound Court is beautiful, starving, and ruled by King Kaelith, a fae monarch with a crown of living thorns and centuries of blood on his hands. He has upheld the tithe because the alternative is collapse. Mortal blood feeds the failing Seal that keeps the Hollowing—a rot that devours warmth, memory, desire, and names—from consuming both realms. Wren should have been one more body given to the old bargain. Instead, her blood answers. Starblood does not feed magic. It remembers it. And Wren may be the first person in centuries capable of rewriting the bargain that built Kaelith’s throne. Read more