Hammerdin

A Hammerdin is a Paladin build involving the maxed-out use of the Blessed Hammer skill.

This build is favored due to the extraordinary damage of the Blessed Hammer, coupled with its synergies, Vigor and Blessed Aim. Concentration Aura also adds damage. It is the most played character build in Diablo II, as Hammerdins dealing 15,000 damage per hammer are not uncommon. However, it is one of the most expensive builds to successfully create, as there are so many Hammerdins out there. A Hammerdin will use his Enigma Rune Word to teleport next to large mobs of enemy, and then hit them with multiple hammers. Many saw this build as being overpowered, and so 1.13 attempted to balance this by removing Blessed Hammer's Demon and Undead immunity bypassing. However, this only slowed Hammerdin Baal runs a little, as people later realized that Holy Bolt can still damage the undead, magic immune or not, and so Achmel the Cursed's boss pack did not prove to be as big a problem as was initially thought.

Skills
A 'basic' Hammerdin setup looks like this: With high end gear a hammerdin ends up having +20 combat skills; an alternate version is to put only 1 pt into Holy Shield and instead put the skill points into either Fire Resist or Lightning Resist to up the max resist cap from 75.
 * 20 points to Blessed Hammer
 * 20 points to Vigor
 * 20 points to Blessed Aim
 * 20 points to Concentration
 * 20 points to Holy Shield

Stats

 * Enough Strength to use gear.
 * Enough Dexterity to reach max (75%) block.*
 * The rest into Vitality.
 * None to Energy.

You will still need dexterity to reach a 75% chance to block, as Holy Shield increases the shield blocking rate, and does not scale directly with your character's chance to block. See below.

For example, a Royal Shield with 55% blocking and level 20 Holy Shield will raise the shield blocking to 80%, however, blocking is capped at 75% (25% while running). A shield with higher blocking rate will require less dexterity to reach the maximum block rate of 75% while a shield with low blocking will require significantly more dexterity to reach the cap.

An alternative version is to keep the base 25 strength and equip an breast plate, and either a Torch (or Annihilus) and placing more stat points into vitality instead. Though this has fallen out of favor in with the ability to reset stat points.

Items for expansion

 * Armor: Enigma Rune Word, in an Archon Plate, Dusk Shroud or Mage Plate (preferable for low strength requirement).
 * Helm: Harlequin Crest Shako, preferably inserted with or Ber Runes, or a Perfect Topaz.
 * Belt: Arachnid Mesh Spiderweb Sash.
 * Rings: 2x Stone of Jordan or Bul-Kathos' Wedding Band rings or a mix of the two. Rare rings with Faster Cast Rate or Raven Frost can also be used here.
 * Amulet: Mara's Kaleidoscope Amulet or Faster Cast Rate +Paladin Skills +All Resistance Amulet.
 * Gloves: Magefist or Chance Guards gloves.
 * Boots: Ethereal Sandstorm Trek Scarabshell Boots, War Traveler boots, or Waterwalk for +5% Max Fire Resist and more Life.
 * Charms: Hellfire Torch, Annihilus and combat skillers.

Maximizing damage setup

 * Weapon: Heart of the Oak Rune Word in a Flail.
 * Shield: Herald of Zakarum, preferably upgraded and inserted with, , or (this is only if you invest absolutely no points into Holy Shield, as Shael only gives Faster Block Rate, not chance, and Holy Shield already reduces block rate to 2 frames) Runes, or Zod Rune if ethereal.

125% faster cast rate setup

 * Weapon: or Heart of the Oak Rune Word (this requires a Faster Cast Rate ring).
 * Shield: Spirit Rune Word with 35% faster cast rate, made in elite paladin shield with all resistance attribute.
 * Gloves:Magefist or Trang-Oul's Claws.
 * Belt: Arachnid Mesh.

Items for non-expansion
It's hard to find perfect equipment in non-expansion but the preferred (or perfect) equipment for a Hammerdin in non-expansion looks like this. Faster Hit Recovery on the Armor, Helm, Boots or Shield could be really helpful too.
 * Armor: A rare Mage Plate with high resistance, +Life and enchanted defense. Good to have -20% or -30% requirements, too.
 * Helm: A rare Grim Helm with high resistance, +Life and enchanted defense. Good to have -20% or -30% requirements, too.
 * Belt: A rare one with high resistance and +Life. Good to have a 4 slot Belt. Perfect if they have +Strength too so you are able to put more points in Vita.
 * Rings: Both Rings should have +10% Faster Cast Rate and high resistance. Perfect if they have +Strength too so you are able to put more points in Vita.
 * Amulet: The Amulet should have +10% faster cast, +2 to Paladin skills and prismatic. Perfect if they have +Strength too so you are able to put more point in Vita.
 * Gloves: Magefist for more faster cast.
 * Boots: Any rare Boots with high resistance. Faster run is quite helpful too.
 * Shield: A rare Grim Shield with high enchanted defense, prismatic (+20 to all resistance), +2 to Paladin skills and Faster Block Rate.

Maximizing damage

 * Weapon: A Scepter with +2 to Paladin skills, +3 Concentration and +3 Blessed Hammer

100% faster cast

 * Weapon: Spectral Shard

Magic find
A Hammerdin is useful for Magic Find runs and to run a party through all difficulties, due to its high damage output. Use Gheed's Fortune, 7% better chance of getting magic items small charms and War Traveler boots to increase your chances of getting magic items. You may insert Ist into and a Perfect Topaz into Shako as well.

Mercenary
A well-equipped Act 2 Defensive Mercenary from difficulty will help, by distracting the enemy and slowing them down with its Holy Freeze aura. Popular equipment for hammerdin's act 2 mercenary is Fortitude Rune Word in ethereal armor, Insight Rune Word in ethereal Colossus Voulge, and ethereal Andariel's Visage inserted with a Ral Rune.

Another alternative Mercenary is the Act I Rogue, using the Ice Rune Word in a high damage Elite Bow such as a Shadow, Colossus, or Diamond, then boosting her attack speed with Andariel's Visage socketed with a Ral rune, and the Treachery Rune Word for armor. This setup was more commonly used for Chaos Party leveling due to Oblivion Knights casting Iron Maiden. However the removed this skill from the Knights' abilities, encouraging the use of Act 2 mercenaries once more.