Necromancer Mark Activation
Personally I’d like to, but that is being greedy if you ask me. If we could activate them then they wouldn’t be much different than a well. I see them more as a magical trap in lore and gameplay.
It’s better to keep your mouth shut and appear stupid than to open it and remove all doubt.
They would still fit the trap aspect, because they wouldn’t automatically activate the effect when they’re set. It would just be a sequence ability, press the skill again to activate the mark or set it and forget it.