Deathspell. Ascendant, #1

In 15th century England, Christian Richardson will do anything to find his father's killers even if it means dabbling in magic. Christian's father is murdered by men who can't be killed by a blade. Only a child, he narrowly escapes with a pendant and a scroll that his father demands he protect. He swears vengeance, but his only clue is the killers' red cloaks and their sigil, a flame within a circle. Forced to look out for himself, the orphaned boy grows into a skilled mercenary.
Christian devotes his life to searching for signs of his father's murderers, determined to confront them. But despite his best efforts, his life isn't entirely about blood and death. A few like-minded souls manage to open the cracks in his heart, and he even finds moments of happiness with Paolo, a fellow mercenary who is also a scoundrel of a thief. Then Christian takes a job where his target fights back with more than a sword.
After years of hunting, his quest for revenge might be nearing an end. But as the trail becomes clear, Christian discovers the red cloaks are far more dangerous than he imagined. Their numbers are vast and some of them are the very nobles waging war over England's crown. There's even a chance not all of them are human. Drawn into their web, Christian must confront more than a band of killers. These are ruthless people with plans and goals that go beyond a single act of murder.
As he pushes forward, ignoring warnings from those who care about him, there are two truths Christian will have to face. His father's true legacy - the reason he was killed. And the fact that using magic feels more natural than breathing.