In a similar vein to my previous question , can a mark from a Fighter, Battlemind, etc. be maintained when the target succeeds on a Stealth check vs. a Defender's passive Perception and becomes Hidden with respect to that Defender?
Stealth isn't a defined condition in 4e. Using the stealth action, on a success, makes the character Invisible and Hidden. For details on the difference, see this question.
These conditions inherently have no special effect on Marking. If you were marked when you become invisible or hidden or both, you are still marked and it ends however it normally would.
In the case of a Fighter who needs to attack to maintain his mark, Invisibility wouldn't do much because he can still attack the target (at a -5 penalty, but a Fighter doesn't need to hit). Hidden, on the other hand, means the fighter does not know where the target is, so attacking to maintain the mark is much more difficult.
The Rules Compendium (p. 221) gives some suggestions for what to do when you cannot see a creature and want to attack it. One of those is to pick a square you think the creature is in, and target your attack there. If you guess correctly the mark could be maintained.
Marks aren't maintained and only end in the following circumstances:
- The creator of the mark dies or falls unconscious
- The marked creature is subject to another effect which marks it. Only one mark at a time, the last one wins. Some marks cannot be overwritten, example: Focus Bind.
- A power or effect specifically says that it ends the mark, an example would be Marked Escape.
Absent the above situations the marked condition last for as long as the power or effect says that it does.
Making a stealth check and going hidden will not prematurely end a mark. If a mark is scheduled to end and the creator of the mark would like to mark the character again then it must fulfill the conditions of whichever power it wishes to use to mark the target.
This just drops down to the basic question of "Can I target a hidden creature?" and the answer (in general) is yes. From the Rules Compendium, pg 105:
- The target must meet the power's target definition.
- The target must be within range or area of effect of the power.
- The target must be within line of effect of the power's origin square.
If you don't have line of effect, it doesn't matter if the target is hidden or not, the target is immune to nearly all powers. If you can't see the target, then some powers that mark cannot be used. Those are pretty rare. The only at-will powers that can be foiled by invisibility (and hence hidden) are augmented Battlemind powers.