(abbr.) Killed On Sight. Refers to the status of certain PCs in regards to certain zones. For example, dark races (Dark Elves, Trolls, Ogres and Ilzak) are KOS in zones like Rivervale and Freeport. Likewise, good races are generally KOS in dark cities. PCs can overcome KOS status by getting enough of a positive faction change with the affected species. cf. faction, GK.