Throne of ashes: a grimdark power progression fantasy

"A ruthless queen tightens her grip on a powerful duchy-and uses calculated ambition to strengthen her rising empire-in the third book of this epic fantasy. Lady Lilliana Silverwater may appear to be a young noble, but beneath the surface lies Lilith, a reincarnated queen who conquered kingdoms and crushed rebellions long before this life began. Having orchestrated the fall of Duke Alistar, she now walks the streets of Elyndor, a city held in careful balance under the temporary rule of the Duke's sister. And with the nobility distracted by the coming succession, she studies her enemies, forges alliances, and lays the groundwork for a takeover no one will see coming. But after surviving a deadly encounter with a mythical hydra, Lilith's buried necromantic powers begin to awaken, imbuing her with unholy magic that threatens to consume her very self. On the hunt for new protections, she seizes the opportunity when a grand colosseum tournament is announced. And the prize is no ordinary weapon but a blade from her past incarnation that grows stronger with every life it claims: Deathbringer.