Aron took a moment to have a look at Vins back. The mark was an arcane symbol of ownership similar to the original cantrip<em>arcane mark</em>. The difference is that it combines domination magic such as suggestion and dominate person with a spell of permanency. The girls mark cannot be removed easily. This is Tal'both magic and you recall that the only means to break the spell is to kill the master or masters. It's possible that more than one of them have the mark. Each of the leader and his lieutenants probably has a master's mark. And until then she will be forever enslaved.