Skraelings, or Skraelingjar are the warriors that guard Miscellania and Etceteria. If you fail to steal from a stall in a Miscellania or Etceteria market, they will say "Get your hands off there!" and attack you.
If you kill him in Miscellania, your popularity rating will decrease, and you will get fewer resources from the kingdom until you gain that popularity back. However, if you kill him in Etceteria, your popularity rating will NOT decrease.