Guide written by Firestorm on the DiabloII.Net Single Player Forums.
As the name implies, this Druid uses skills that look similar to those that Big-D himself uses. This can be called a sub-class of the Elemental Druid, except that instead of using pure elemental skills, the Diablo Druid also uses skills from the summoning tree. Main reason: Firestorm and Arctic Blast don't do scrap in mid Nightmare and Hell mode. With minions and a Might mercenary, the creatures themselves can actually take on monsters by themselves. When it comes to the bosses (mid Nightmare and Hell), its time to call some friends to help you through.
Firestorm (Diablo's Fire Snakes) Skill Points: 1
I don't suggest you invest heavily in this skill, though you might want to do so. With equipment, a lv 32 Firestorm is possible.
After a bit of testing, I realised that all three "fire snakes" meet at where the mouse is when the the spell is cast. To clarify, if you click at say point x on the screen, all three snakes will meet near, if not directly at point x.
Note however, that it meets around 90% of the time, not 100%. One direction where it almost never meets (one snake strays away) is to the north-east of where your druid is.
When maxed, and boosted to lv 32, these "snakes" can do a lot of damage ... especially if they all pass under a monster at the same time, and if the monster is huge.
Artic Blast (Diablo's Pink Lightning Bolt of Death) Skill Points: 20
This doesn't really look like Diablo's PLBD, but it does imitate it well. I suggest you max this skill; at high levels, the cold damage pretty high. With my recommended gear set up, this skill can reach lv 31.
It is mostly a "support" skill for your minions as its range is reasonably long (at high levels of course) and monsters who get hit by a blast of the cold air would get chilled. (They become blue, move slower, and attack slower.) This does not affect cold immunes though; unlike Holy Freeze.
These are the only two skills that matches what Big-D uses, so stop at that. There is no need to proceed further down the elemental tree.
(Even the higher level ones don't do much damage anyway)
Ravens Skill Points: 1
You're not going PvP, so there is no need for points here. (Some use ravens to stun-lock an opponent in PvP.)
Spirit Wolves Skill Points: 1
"What about attack rating? Don't my minions need it?" Don't fret, young druid, with +skills (which this druid is heavily dependent on) this skill will be boosted to lv 8, which is enough.
Dire Wolves Skill Points: 3-10
Even with +skills, you might consider investing in this skill so your minions will have more life. Remember, in this build, minions are your main killers. You simply play the support role.
Grizzly Skill Points: 1-10
To enable your minions to actually kill anything, investing in this skill will be wise.
As for which creature to use, I personally prefer 3 Dire Wolves. Think about this scenario:
Out from the darkness of Mephisto's Lair comes a Gorebelly. If you had just one Grizzly out, the Gorebelly can easily stun and kill it. With three Dire Wolves, they stand a better chance against him. Of course monsters come in packs, but if your wolves can't deal with them, at least they make a bigger meat shield.
Oak Sage Skill Points: 1
This skill is a preq. Don't put more than 1 point.
Heart of the Wolverine Skill Points: 20
Max this. This gives a good damage and AR bonus to your wolves/grizzly and your hireling. In addition, if you are using a bow, this will come in handy.
Poison Creeper Skill Points: 1
Preq only.
Carrion Vine Skill Points: 1
Let your +skills do the rest. This will be your main vine, as mana shouldn't be a problem. If you maxed Firestorm, high chance you will be standing right in front of an enemy before casting it. This vine helps you recover the life you lose while being a "hero".
None. Simple as that.
Please note that due to a bug, skills beyond lv20 gain no bonuses. This should be fixed in version 1.10 though.
Jalal's Mane Gives a +30 all resistance bonus which will come in very handy. In addition, it gives the +2 to all druid skills which is what this build depends on heavily. Has +20 Strength and Energy, which helps you to "save" stat points. Dump these into Vitality and Dexterity instead.
Harlequin Crest Shako Possibly harder to find/trade then a Jalal's. Has 10% DR and life bonuses in exchange for +30 all res and dual stat. Also has the all necessary +2 to all skills. Jalal's is better IMO.
Mara's Kaleidoscope This ammy is useful for the +2 all skills. The rest of are all just "gravy" ... delicious ones at that.
Other +2 Druid skill ammys + to skills is the main thing you will be looking for in an ammy. Since you are not going melee, you won't need any leech on them. Resistance or life bonuses will be good. If you intend on using a bow, you might want a dual leech mod on it.
Earthshaker Battle Hammer Main stat of this item: +3 to elemental skills. The strength requirement of this item is rather steep, so you might consider Hel'ing it.
Dark Clan Crusher Cudgel +2 to all druid skills. This is another good weapon to use. It really depends on what you see more important: higher elemental spell damage or better minions. Personally, I would go for this.
Kuko Shakaku Cedar Bow
This is another alternative. Load up your druid with lots of poison charms, grab this bow, and start poisoning monsters while your minions soak up the damage.
The Fire's Explosive Arrows mod will help you hit your target 100% of the time.
Lidless Wall Grim Shield
Gives that precious +1 all skills bonus and extra mana.
Gloom's Trap Mesh Belt
Add's to the maximum mana of your druid and vitality.
String of Ears Demonhide Sash The PDR and life leech might come in handy for your druid especially if he is going for the Firestorm "hero" route or using a bow.
Silkweave Mesh Boots
Add's to the maximum mana of your druid. Has a good 30% fr/w bonus too!
Frostburns Use this if you seem to be running short of mana every time you try to "frost blast" a pack of enemies.
Magefist For the Firestorm / Armageddon users. This glove gives your fire skills an addition boost. Good for hitting that lv 32 Firestorm mark and brag about it. Just don't let others see what pathetic damage it does.
Stone of Jordan
Try to get two of them. The +skills and additional mana is always welcome.
As the main monster killing force of the Diablo druid is his creatures, an act 2 Might mercenary will come in handy. They are available in NM Act 2, and are listed as an offensive type.
Please note that this build is not exactly viable in hell mode since monsters would have much higher hps. Another problem you might encounter would be lightning enchanted bosses. These can kill your minions amazingly quick. A good way to counter such creatures will be to use the "high poison damage + kuko bow" strat.