Why would it need to be magic? At the simplest Tom could create a new shrine type building that every noble meeting some requirement could build, which would limit daimon cultist spread. Or he could allow nobles to go all inquisition in a region and burn out daimon followers. Once you break the current systems limitations the options are endless.
Tools which would have been logical to add even before a daimon invasion. I, for one, have long argued that the religion game would be better off if we involved non-priests in it a lot more.
Persecuting the cultists still hurts your realm, though.
I know I'm sounding awfully negative. That wasn't really my goal. I'm actually quite hopeful. With the declining player base, I kind of lost all hope for BT's future, so I'm wishing it gets a burial worthy of all the excitement it provided over the years.