It seemed to me like the cleric knew the password. That's why he was telling Haley that it was a good thing she brought Belkar to him. He even knew it came from the lord of Azure City, and was even ready to cast it on Belkar (hands glowing and everything).

It does seem that they may need Belkar's help to defeat the thieves' guild. Haley, a cowardly cleric, and a pacifist slyph seems to be a poor match up. Maybe Belkar can make a deal with the cleric, remove the mark and Belkar will protect him? Or maybe Haley will just concede she still needs his help.

Anyone want to bet that the password for the mark is "Mr. Scruffy"?