St. Claires Skill

[LouisdeFuines]

How does that marking skill work correctly?
I tend to use it often, but seldom my companions join in shooting the marked target.

Can someone please explain me the skill?

For example: My boss sees 3 enemies, but the skill is locked. Why?

 

[bolly1980]

From memory, when you select Stephanie St Claire a coloured circle around her will indicate which of your friendly units are within range. These units will then fire at the target you select provided that they have line of sight to the target. If the action is locked, and assuming you have sufficient action points and that the action is not in cool down, it could be that there isn't a suitable target in range.