This strategy no longer applies to the latest version of Diablo II. It remains here for archival use only.
Grim Ward is a level 24 skill from the Barbarian Warcries tree. This obscure skill offers powerful and reliable crowd control, if used properly. So whether you are building an Uberchar or exploring a skill-path less traveled, you will at least want to know what this skill can do for you, to decide whether or not it will fit into your plans.
First off, the skill's method of operation (in terms of when and how it takes effect on monsters) is not what I'd call infallible. Apparently the monsters get some sort of saving throw, or the percentage chance to affect them is applied per frame. It is possible, though rare, for non-boss, non-champ critters to walk right through your ward. More common is for them to enter the ward radius and be affected at some point, which varies case by case.
This is because Grim Ward affects moving monsters. It will not work on them while they are standing still. This makes using the Ward as a stationary Howl somewhat ineffective at times, if your intent is to raise the ward then continue standing there. On the other hand, the ward can be *extremely* effective with a more mobile approach to utilizing it. You can scatter massive mobs with only one low slvl ward and end up fighting enemies one or two at a time, once you get a knack for it.
Thirdly, wider radius means increasing effectiveness twofold, since you not only gain a wider area but also more time inside the ward area for any enemies passing through it, thus greater chance of affecting them before they reach you.
Fourthly, scared creatures have an almost dim-vision-like singlemindedness in that they will not bother you unless you bother them first.
Finally, the direction frightened creatures take is a beeline AWAY from the ward. If they happen to be right on top of the ward when the fear takes effect, they will just stand there. If you set up multiple wards, you can get a pinball effect going, where the critter runs from this one, then that one, then another one, until escaping the area of effect.
With all these things in mind, the most effective way to utilize a ward is as a buffer. By this I mean positioning: move to a location that places the ward between yourself and approaching enemies and they will almost certainly be affected before they can pass through the ward area. This works to some degree like a minion, in that amazons can raise a decoy or valk to distract enemies, and necros have their minions. Grim ward seems to work best for me when I treat it as a stationary minion: a scarecrow. Now it won't damage enemies and it won't hold them still, so this is not a good way to help a sorceress get a quick firewall kill, or to help an amazon take down a target with bow or jav. On the other hand, grim ward cannot be killed or destroyed or affected in any way by the enemy, and it is well capable of distracting not just a couple of foes, but frightening away and scattering even the largest mobs. You are somewhat constrained in your positioning by where the corpses fall, but the mana cost is very low and you can raise several wards if you have the bodies to do so. Mobility is important in using wards. They are vastly more effective if you stay on the move and change position prudently as needed, than if you simply try to stand still inside the ward.
Grim ward is a fantastic solo-play skill. If you are fighting alone, particularly against enemies who can pack a mean melee punch, you can scatter whole mobs and pick them off one by one almost at your leisure. You don't even have to risk exposure: corpses from your last fight can do just nicely. All you have to do is leave a corpse or three untouched, and retreat to them and raise wards if you encounter or awaken any mobs.
The bane of Grim Ward is a champion 4-pack. You can't stop them. At best, you can scatter any normal monsters that are also after you, but the champs you will have to deal with by other means. A boss is also a problem, but at least you can scatter the minions and then try to take on the boss directly, or buy time to figure out what else you can do.
"Maypoling" is my term for my standard Grim Ward tactic, particularly outdoors or in any area not completely cramped. Raise one ward and then swing around it as enemies approach. If there are a lot of them you should raise a second ward if you can, but a typical mob (unless you're reckless) only has about 4 to 6 critters and you can easily swing around the ward to scatter any approaching monsters and have your way with them one at a time. This is particularly useful with fast-moving enemies, whose strength lies in swarming you, especially in cramped spaces.
I haven't tried this skill in multiplayer yet, but I can imagine all kinds of uses for it. However, they all require some understanding of the skill on the part of your allies, since the ward won't help them if they don't bother to position themselves in ways to take advantage of it. However, sorcs and amazons and even necros can gain cover, and paladins, amazons and other barbs can vastly reduce their exposure to enemy melee attacks while fighting, if they have the wits to take advantage.
For you see, once raised, a ward is a passive thing and any player can take full advantage of it the same as the player who cast it. It's in their hands at that point, based on their maneuvers and positioning. This multiplies its effectiveness for them, since they can control the effects all by themselves and gain as much advantage as they have skill for doing so. Contrast this with Howl and Terror, the other two fear skills, which are left solely in the hands of their caster. In this regard, then, your allies can RELY on the wards you raise in ways that Howl or Terror can never even begin to approach.
Grim Ward clearly cannot rule all situations, but it's power has not yet been understood by players. This is a skill that does not compliment Whirlwind, where the aim is to group targets as closely as possible so that you hit them all in the same pass. Grim Ward is for the non-WW barb, yet offers massive potential from a tactical sense: the thinking barbarian's skill! If combined with skills from other players, such as Holy Freeze, Necro curses, Cold Spells, Static Field, or any AoE spells... well the tactical possibilities are complex, to be sure.
With WW no longer quite as strong, particularly in dealing with the largest crowds of enemies, Grim Ward should be considered. It can be used with only a few points dedicated, and only 2 prereq points for skills that are fairly well useful in themselves. More points may make it more effective, or they may not matter. I don't yet know with any certainty what, if any, the "optimal" skill level is for this skill, regarding whether or not there is a point of diminishing returns.
One note of warning: I have on three or four occasions seen a "dud" ward: a casting that had no effect. The ward is raised but does not affect any foes. There may be some bugs in there with this skill, perhaps having to do with competing for the corpses with shamen and their ilk. Or maybe it was something else. In any case, keep an eye out. If a ward doesn't work for some reason, you need to raise another. This is a very rare occurrence though. I've seen it only a couple times in many hundreds of uses.
Fans of Howl have got to try Grim Ward for themselves. :) Howl has its uses as an emergency spell, particularly in dealing with stairs traps -- you don't need a corpse, you can cast it right away. However, in the larger picture, Grim Ward offers manyfold more strategical possibilities, limited only by the imagination and skill of the player.
DaShiv asked: "Did you notice any diminishing effectiveness for grim ward as mlvls (monster levels) increased? Especially in cases as mlvl increased faster than your clvl, as supposedly in these situations howl does not work very effectively."
Grim Ward is very different from Howl. Howl is a one-shot deal, it either works on foes or does not. Same with Terror and even the Howling effect. Either they are scared or they are not. You use it to thin out a crowd, but the crowd may not be thinned all that much in the situation you describe.
On the other hand, Ward is based on monster movement through the area of effect and makes repeated checks. This much seems clear to me. As I have already described, Ward is vastly more effective with a mobile approach. By this I mainly mean that you move around in such a way as to repeatedly and continuously force approaching enemies to walk/run through the ward area and they WILL ALL be affected sooner or later. So it hardly matters if they are resistant. Just keep on the move and keep them exposed and they will run. Sometimes immediately, usually by the time they are halfway through the ward area, and almost always before they can pass all the way through, in my experience.
Now I have not taken on any critters more than about 10 mlvls higher than my clvl , so I can't speak directly to that, but I am positive that even if the effectiveness is cut a lot by vastly higher mlvls, the principle of continued exposure to the area of effect will lead to solid and reliable skill effectiveness. You *may* need to pump the skill to get a wider and wider radius to be solidly effective if facing vastly higher mlvls, or opponents who are so quick as to cut quickly through the area of effect, but if you understand how to use the wards in a mobile, positioning way, as a measured tactical approach instead of an emergency relief skill, I'm positive that it WILL be effective for you. This skill might well allow barbs to "jump ahead" in difficulty without use of whirlwind, and has great untapped potentials for coop play. It's NOT infallible, but those repeated checks on the monsters are the main key to why this skill ultimately blows away Howl in all but two situations: when you have already been swarmed, and when you don't have a corpse handy (a problem you can avoid with prudent play, with some exceptions like stairs traps or if allies use up all the corpses).
DaShiv asked: "Similarly, did it work the same across all the difficulty levels, or was the "fear" time reduced for NM/Hell?"
Let me tell you this: some critters (in Nightmare) would run and NEVER STOP. They would flee and flee, and even chasing them down they would not fight back but only seek to flee even more, sort of like the ghoul lord, sand raider and spider class monsters sometimes do when hurt. I'd say fully 15% of monsters affected, would be scared so badly they became irrelevant. Some others get caught right on the ward and can't move. Many run for a long long time and come back 5 or 6 seconds later, if at all. Most run only for a couple of seconds, then get affected and run again, and again and again, because I position myself until I'm ready to take them on. This is even a lag-friendly skill in that once raised, the ward's effects are server side and any allies can take advantage, and any monsters will be affected, regardless of YOUR lag.
Howl may well lose effectiveness in that it's a one-shot affect, and if that fails, it fails. Ward, if properly used, is a continuous repeat affect and should be able to cut through any resistance or lessened effect to still be highly effective, even if not quite AS effective. I've literally seen some poor saps in Nightmare bounced around 6 or 7 times by a group of wards, which is actually BAD for Thrower since they end up dodging his shots in that situation. :) I have to be careful to line up on running enemies in the same ray of travel (or close) as they are fleeing, or else my shots always miss behind them, and that's not good. Use of Ward does sometimes cause me to waste ammo this way, sometimes in sizeable quantities, but I am learning to reduce that, and the defensive aspects of the skill are simply indispensable.
After DaShiv asked these questions, he completed a Hell-Difficulty run and used Grim Ward at only skill level 1 (+1) and reported it effective against monsters even 40+ mlvls higher than his clvl. Therefore, unless you are planning to level up slowly with your Barbarian, sticking within or near the full experience range, you will find Howl unreliable later on, and should focus instead on Ward.
One final note. In order to get Grim Ward, you will have to spend prereq points into Find Potion and Find Item. Since you will have these skills, you may as well use them, particularly if you get any boost to them from +skill items -- just don't go nuts and leave yourself without corpses to raise wards. Also, don't eat up all the corpses if one or more allies relies on them.