Alter Aeon Online Help

Keywords are:  'pkok rank'

Format:
who rank

Players who player kill often will be given a ranking, which is a score
used to determine who the most powerful player killers are.  There are two
different categories of rank:  temporary player killing, and arena kills.
A higher rank means a more successful kills and probably a more powerful
player killer.

In order to increase your rank, you must defeat another player that is
within about 200 points of your rank.  If you rank too high over another
player, you will not gain any points should you win.  On the other hand,
if you lose to a lower ranked player, you will lose points.

Keep in mind that even a low rank is better than no rank at all.  Players
with no rank have no player killing experience at all.