This guy and friends Cei Sunjumper and Slea Pinewhisper are not at the locations described when in the Old Commonlands open zone. (I'm not sure about the instanced zones for OC missions.) Here, they're all at the Army of Light camp in the tunnels, right next to quest-giver Innkeeper Grang. Both Cei and Shadow attacked me while I was trying to talk to Grang. Slea minded her own business.
Somehow I managed not to kill them, so I didn't get to find out what faction they're on. Probably Jaggedpine and Protectors of Pine. I should go work on that someday....