"Oh my Khersis", derivative of "OMG". Khersis is the mail god of humanity in the web novel Tales of MU. The OMK expression was born in the reading community as an in-universe expression used by the community.
"OMK! You beat the SCARECROW? On your FIRST TRY? But that’s the last boss! NO WAY!!!" - one of the comments from Chapter 177
by nobodez March 30, 2008