Is this the Demon Cycle series by Peter V. Brett...? The series is comprised of five main books, with the first having been published in 2008 and the fifth in 2017.
Here's the Goodreads synopsis for the first book in the series, The Warded Man (2008):
As darkness falls after sunset, the corelings rise—demons who possess supernatural powers and burn with a consuming hatred of humanity. For hundreds of years the demons have terrorized the night, slowly culling the human herd that shelters behind magical wards—symbols of power whose origins are lost in myth and whose protection is terrifyingly fragile. It was not always this way. Once, men and women battled the corelings on equal terms, but those days are gone. Night by night the demons grow stronger, while human numbers dwindle under their relentless assault. Now, with hope for the future fading, three young survivors of vicious demon attacks will dare the impossible, stepping beyond the crumbling safety of the wards to risk everything in a desperate quest to regain the secrets of the past. Together, they will stand against the night.
The Wikipedia page for the first book offers the following description of one of the main characters, Arlen, who eventually becomes known as 'The Painted Man' due to the combat wards marked on his skin:
Arlen is introduced in the aftermath of a coreling attack that claims 27 lives. Those happen often, usually due to marred or misplaced wards. He realizes that humans have been mostly on the defensive, hiding behind wards. During an attack which endangers his family he overcomes his fears of the corelings and attempts to fight them off, though with little success. He is disgusted by his father's cowardice after his mother is attacked, and leaves his home to seek training as a messenger, a traveling warrior-nomad responsible for maintaining trade and communication links between villages. As he matures he becomes determined to hone his skills and help turn the tide against the corelings. In the second half of the story, Arlen discovers the lost combat wards inscribed in the ruins of Anoch Sun. Betrayed by the men of Krasia, he uses the wards on himself, becoming "The Painted Man".
Another of the main characters mentioned on the Wikipedia page is Leesha, a 13-year-old girl:
Leesha is a thirteen-year-old girl who lives with her abusive mother and downtrodden father. After a slanderous rumor spread by her fiancé seems to destroy her chances of a respectable marriage and shows the true nature of many of her friends and the hypocrisy of the villagers, she devotes herself to learning the ways of herb gathering to care for the sick.