Highlander’s Wounds of Eternity by Agnes McNair

He was cursed to an existence of solitude.
Untouched by the consequences of time, he wanders the Highlands with no purpose.

Colleen Cunningham, a resilient young healer from the vulnerable village of Aberkin, lives her life in constant fear as a bloodthirsty laird threatens her people’s safety. When fate brings a severely wounded warrior to Collen’s doorstep, she compassionately tends to his injuries, though her heart fears the inevitable.
Little does she know that this mysterious stranger, known as Arran of Sterling, harbors a timeless secret hidden for centuries in the depths of his very being; Arran is immortal. He can be hurt, but never killed. Because of this curse, he has spent countless years as a mercenary, hiding away from human connection, resigned to an eternity of loneliness.
As Colleen’s allure and unwavering kindness break down the walls around his heart, Arran finds himself irresistibly drawn to her. He vows to protect her and the people of Aberkin, even when the ache of longing threatens to consume them both.

In the midst of uncertainty and danger, their forbidden love blossoms. Can their passion defy the constraints of fate and time itself?