Gotcha re: DC and it's mark being linked.
Can I assume that the mark provided by Piercing Smite does nothing more than set the target up for additional damage from something like Holy Strike? i.e., a mark applied by Piercing Smite does not cause a -2 to the creature's attack role if you are...
This actually helps clarify my thinking around Piercing Smite and marking. If you distinguish that a mark and a divine challenge are two different things, now attacks like Enfeebling Strike and Holy Strike make much more sense, especially after throwing out a Piercing Smite in a group...