World at the Lake's Edge Series by Lyndall Clipstone

When Violeta Graceling and her younger brother Arien arrive at the haunted Lakesedge estate, they expect to find a monster. Leta knows the terrifying rumors about Rowan Sylvanan, who drowned his entire family when he was a boy. But neither the estate nor the monster are what they seem. As Leta falls for Rowan, she discovers he is bound to the Lord Under, the sinister death god lurking in the black waters of the lake... moreWhen Violeta Graceling and her younger brother Arien arrive at the haunted Lakesedge estate, they expect to find a monster. Leta knows the terrifying rumors about Rowan Sylvanan, who drowned his entire family when he was a boy. But neither the estate nor the monster are what they seem. As Leta falls for Rowan, she discovers he is bound to the Lord Under, the sinister death god lurking in the black waters of the lake. A creature to whom Leta is inexplicably drawn… Now, to save Rowan―and herself―Leta must confront the darkness in her past, including unraveling the mystery of her connection to the Lord Under. less

Some oaths can never be broken. .. The curse that haunted Lakesedge Estate has been broken, but at great cost. Violeta Graceling has sacrificed herself to end the Corruption. To escape death, Leta makes a desperate bargain with the Lord Under, one that sees her living at his side in the land of the dead. But this world of souls and mist hides many secrets. And when Leta realizes she is still connected to Rowan by a tethering spell, she will risk everything— even her soul— to try and reach him... moreSome oaths can never be broken. .. The curse that haunted Lakesedge Estate has been broken, but at great cost. Violeta Graceling has sacrificed herself to end the Corruption. To escape death, Leta makes a desperate bargain with the Lord Under, one that sees her living at his side in the land of the dead. But this world of souls and mist hides many secrets. And when Leta realizes she is still connected to Rowan by a tethering spell, she will risk everything— even her soul— to try and reach him. Torn between power and love, life and death, Leta struggles to keep hold of her humanity as she falls further and further under the spell of the world Below… and the Lord Under. less