I'll not lie to you: Curse Necromancers are slower to gain levels with than any other style, they are slow to make any progression at all, they may as well forget magic find equipment, and they cannot play high-player games (though I've been highly successfun in four-player games myself). Why the hell play one then? I'll give you an example from my playing experiences: picture several groups of two Urdars all together in one-on-one boxing matches, the results of which being controlled by you and as they defeat their first opponent, they meet a new one until at last there is only one left (barely) standing - who you promtly slay by your own hand, lest he get any big ideas about selling movie rights. If you think that sounds funny, then you share my sense of humour and should try the style (no, it is not a variant).
Making a Curse Necromancer is a very personal thing: you need to make it to suit your playing styles. Here is how I suggest you look at things.
Strength: You'll probably not want to put too much into this, depending on how you want to play. If you want high defence, go nuts here. Pesonally I suggest picking an ideal weapon and get the strength requirements for it. I'd not recomend neglecting this attribute, but you could keep it very low and aim for items such as the Wall of the Eyeless and Magefist.
Dexterity: This attribute can be neglected, but I'd not recomend it. I would suggest, at a minimum, getting the Dexterity requirements for your prefered weapon (if it needs any), but you may also want more or blocking, and even more for attack rating. However, you could always cheat out and never melee thus not ever want to add points to this: I do not recomend that!
Energy: The best thing about a Curse Necromancer is that curses are not particularly draining on the old mana ball. You'll definitely want to add a bit to this, but I'd say if you got to 100 Energy you'd never run out of mana...unless you are a total maniac, or stupid enough to try and play solo-8.
Vitality: Curse Necromancers get hit, and it sucks; never fear, though, for vitality is here! Curse Necromancers need to have higher life than other Necromancers, but since they don't need much mana they can afford to divert points from energy to vitality. How much you need depends on your style, but you cannot have too much: if you don't need the points elsewhere, then this is the perfect place to dump your spares.
There is not really much that a Curse Necromancer needs, and could very easily be played naked: if that is your style, then you should! However, if you prefer to wear some gear, then here's some suggestions. Please note that this way of playing is all about style, so make sure you wear your trendiest gear: no flares!
Weapon: There's two weapons a Curse Necromancer shall want: a casting weapon and a melee weapon. The casting weapon should have Fast Cast, and perhaps a bonus to skills, and shall be your primary weapon. The melee weapon is for Act Bosses and any critters left over after you slaughter the group they were once with. I personally use two weapons for melee: an Ignores Target's Defence weapon for regular critters, and a Fool's Weapon for Act Bosses. You may prefer to exclusively use high-Attack Rating weapons, but I quite like my Spineripper.
Helm: Well, in my opinion you should wear a skull here - it just looks appropriate. Wormskull is great, as it looks like a nice, mouldy skull, yet also has some useful stats. If all else fails, some resistances would be handy, or maybe a Hexing/Blighting/Accursed Circlet, not that you'll really need the skill bonuses.
Armour: Boneflesh looks perfect on a Necromancer I believe! However, the best armour possible would be Artisan's [Full] Plate Mail or Ornate Plate of Stability - you get the same look, but can also socket in TalRalOrtThul for +30% Resistance to all elements. However, I've never found that, so the next best thing is anything looking good with resistances, perhaps Caster crafted armour, or just about any mage-oriented unique/set item.
Shields: Wall of the Eyeless, perhaps with a Perfect Diamond socketed in, is perfect - Faster Cast Rate and style points! Failing that, you cannot go wrong with Ancient's Pledge or Rhyme. If you have both, then use the Wall of the Eyeless with your casting weapon, and your runed shield with your melee weapon.
Gloves: Trang-Oul's Claws would probably be perfect, but I've never found them myself, but Magefist works great with its lovely bonus to Cast Speed. Caster crafted gloves or just any resistances are also handy; a little Increased Attack Speed is also valuable, for when you are forced to melee.
Belt: Anything with resistances, and perhaps a bonus to life, works great here. I recommend using anything with three rows, but you might like to use a Lenymo or something.
Boots: Increased Run/Walk speed is invaluable! Resistances are not bad to have either, if you are lacking.
Jewelry: Resistances are as good as ever, as are life bonuses, and perhaps some attack rating bonuses for when you melee stragglers. Faster Cast rate is also valuable.
Curse Necromancers don't have a lot of choice for skill point allocation. Do not touch the summon tree at all, if you do dare not call yourself a true Curse Necromancer! As for the Poison and Bone tree...well, I see no problem in using Bone Armour to make Normal Difficulty more manageable (especially the early acts), but nothing else - and past Normal Difficulty you'll likely use nothing bar curses. As for the curses themselves, this is purely personal. When plotting your ideas, remember that a Curse Necromancer uses all curses, switching as required.
One example of personalising your allocation might be a player who only ever party with Sorceresses: they would add less to Amplify Damage and more to Lower Resistance to assist them, while a solo player would want an even mix of both. A particular curse of personal choice is Confuse: adding more points is advisable for later difficulties, but as it increases the radius a lot of people don't like adding too many - only your style can determine what suits you. I'd suggest going to chippydip's skills page to make a plan for yourself before you start, but be prepared to change your plan as your style evolves.
The most important aspect of the Curse Necromancer is the obscene use of curses. If you have Lord of Destruction then you can have the 10 hotkeys you need to play a Curse Necromancer effectively, while if you have standard Diablo II you'll have to make do with only eight by selecting two little-used curses and accessing them the slow way. If you do not use at least three different curses in a sizeable battle, then you could have found a more artistic way of handling it. You should move a lot, and try to think of new ways of handling things, combining techniques, and all round try to have a good time. Please note that it's hard to find people to party with who share your love of torturing your prey, and they will likely jump in and kill those Urdars mid-bout. If you can find people who appreciate your efforts, though, then try and get into games with them as often as possible.
The other aspect of the Curse Necromancer is melee: you can use curses to kill things down to the last one...but that guy just will not die when you tell him what you think of his mother! Now is when you stop cursing, switch from your wand to a nice, big weapon to smash their skull with it: this is the only way to logically handle an Act Boss, and the recomended way for handling the only survivor of a once mighty pack. Although you can have a Vile Mother killed by her own children (that is pure class!), those children are a pain to kill off with curses alone so grab a weapon and show them paladins how a real melee fighter handles it!
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