The mark of Kekfadlorem.I’ve heard of it, but I’ve never seen it. -A knife with that mark is the only thing that will kill a Kek demon. Could be very useful. -Especially if Kek demons weren’t extinct.-They are ? Oh dear. Well, - perhaps there is one out there hibernating, eh ? Ready to wake at any moment and embark on a grisly rampage. -I’ll keep my fingers crossed
―Angel to Wesley[src]

The Mark of Kekfadlorem was a mystical symbol engraved on knives used to kill Kek demons, a demon species believed to be extinct. Cordelia Chase used the knife owned by Wesley Wyndam-Pryce to cut a brownie cake much to the annoyance of Wesley.