[In combat anytime you have cover OR concealment from ALL enemies you may make a stealth check.]
"Where in the PHB does it say this? If you attempt a stealth attack against a target, what matters is the target's perception check, not any other monster's. A stealth check is made in conjunction with an action you are attempting to perform stealthily."
[As long as you maintain cover OR concealment from ALL enemies you remain stealthed. After you win a stealth check creatures are allowed to make a perception check on their turns as a standard action against your stealth check.]
"Again, where does it say this? Stealth is associated with actions. It is the action a player attempts stealthily that prompts a DC check, not simply "being stealthed", which is a 3e concept that doesn't apply to 4e. Stealth isn't modal, it's a method."
[Allies grant you concealment ie: standing behind an friend would make you harder to see.]
The PHB indicates allies grant cover (physically blocking ranged attacks); not concealment.
"Can my dragonborn rogue stealth if he stands behind my halfling paladin in the middle of a battle? Do enemies just forget the dragonborn is there?"
"Can my rogue carry a large wooden block, "The Concealer," drop it at his feet in an adjacent square, and then claim he can stealth?"
"Can my warlock stealth by using his shadow walk as concealment? Why don't the monsters pay attention to the misty, shadowy, swirly warlock-shaped object in the middle of the room? If this was intended for warlocks, why isn't stealth on the class skill list?"
It's a shame you didn't bother to calculate.Forrester said:A 1st level warlock that changes his quarry to d8 damage is doing (let's max it out) d10+d8+4. A ranger . . . well, they suck, too bored to calculate.
Even if you assume it's merely an extra 3 damage a round vs the warlock (who gets to attack against Fort), that's a 20% advantage. The ranger is going up against AC, meaning we'd prefer to use the rogue's 19.5 damage as a comparator, which will CRUSH the ranger.
Brokenkingdom said:Yes, you can absolutely hide in a heavily/lightly obscured square. The monsters DO notice the misty-warlock-shaped-area however as the warlock is concealed they cannot get a clear view of him/her. IE: the whole concept of concealment. If the Warlock makes the stealth check on that action it WILL incur a penalty of -5 for moving more then 2 squares, as per the requirement for shadow walk, on said stealth check against their PASSIVE PERCEPTION. Shadow walk was NOT intended to be used by warlocks to gain stealth advantages. It is obviously intended to grant warlocks a bonus to their defense by way of -2 to hit said warlock.
Shadow Walk does not cause the square the Warlock is in to become Obscured.
Two that directly helps a Warlock being concealed.until you provide an ability that garnishes bonuses for the warlock being concealed
Brokenkingdom said:The "ALL creatures" part comes into play under the idea that if a kobold was creeping up behind your friend and he/she didn't notice it but you did, you would shout "Hey buddy watch out behind you" effectively making your friend "aware" of the sneaking enemy which in turn means it is no longer stealthed from your friend. As stated it is up to the DM's discretion to allow/disallow this depending on the situation. See the circumstance I had mentioned before.
You are again taking verbiage from the PHB that applies to out-of-combat stealth situations and applying it to in-combat stealthing. It doesn't matter if an army of 100 minions can see you behind your cover; if you have cover against a target and beat that target's perception check, you gain combat advantage.Right there. Again I state ALL enemies for reasons mentioned earlier and as ALWAYS it is up to your DM.
Regardless, allies still grant cover and cover is still grounds for a sleath check and my statement stands, though thank you for pointing out that mistypen discrepancy.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.