The Harpers are a loose organisation that attempt to keep balance and fight villainy across Faerûn. A group of Harpers can be met in Chapter Two. Led by Jaheira and holed up at the Last Light Inn, they work on opposing Ketheric Thorm. Depending on the route they take, the player might first meet them at the inn, meet some of them travelling the Shadow-Cursed Lands, or find them orchestrating an ambush against Kar'niss – an ambush the player might help or thwart.
If Jaheira joins the party, then she'll want to meet up with her Harper contacts during her personal quest in Chapter Three.
External Links
Harpers on the Forgotten Realms Wiki