Just datamined, it's an elf customization.
NEW Return to Lordaeron Complete the Return to Lordaeron storyline.
Reward: 'Of Lordaeron' Title, 'Dark Ranger' Elf Customization
NEW Return to Lordaeron (Hidden Character Achievement) Complete the Return to Lordaeron storyline.
https://www.wowhead.com/news/dark-ra...rdaeron-327215