Explosionmancer

Explosionmancer, or Explomancer, is a Classic Diablo II Necromancer build which focuses on the skill Corpse Explosion. Corpse explosion is an extremely powerful spell at high levels and can easily kill monsters.

This build is generally only effective on multiplayer games, since it relies on other players to make the first kill.

Amplify Damage
Corpse Explosion is 50% fire and 50% physical damage. Amplify Damage increases physical damage +100%, so it increases the total Corpse Explosion damage 50%. You need more than one point here. The reason for maxing this is that the radius increases, allowing you to cast it on all enemies (even those off-screen), so you can spam corpse explosion on enemies you can't even see.

Corpse Explosion
After another player has killed an enemy, cast Corpse Explosion on its corpse. This will cause area of effect damage around the corpse, dealing 70-120% of the corpse life in damage. How many points you put here is up to you, but it is best to max it

Safety Skills
The spare skill points go into two safety skills. Fire Golem makes the best tank, because it has the most life in mode and can absorb fire. Bone Armor is another safety skill.

Chaos Sanctuary and Corpse Explosion
Since Storm Casters have the lowest combined Fire/Physical Resistances, use Corpse Explosion to kill them.

Summoning Spells

 * Clay Golem 1 skill point (prerequisite)
 * Blood Golem 1 skill point (prerequisite)
 * Iron Golem 1 skill point (prerequisite)
 * Fire Golem 2 skill points (fire absorb 45%)
 * Golem Mastery 20 skill points
 * Summon Resist 3 skill points (39% resist)

Poison and Bone Spells

 * Teeth 1 skill point (prerequisite for Corpse Explosion)
 * Corpse Explosion 20 skill points
 * Bone Armor 1 skill point (470 HP absorption)
 * Bone Wall 20 skill points (synergy with Bone Armor)
 * Bone Spear 1 skill point (prerequisite)
 * Bone Prison 10 (synergy for Bone Armor)

Curses

 * Amplify Damage 20 skill points

Attribute Points

 * 34 strength is to wear a 3-socketed Large Shield which can be bought from Charsi in Act 1 Mode
 * 38 strength is to wear the minimum strength exceptional armor (Ghost Armor)

Mercenary
Because this build needs corpses, it's best to avoid cold-based Mercenaries which can shatter monsters' bodies and leave no corpses. A Defiance or Might aura Act II Desert Mercenary can serve as a tank and corpses-maker for an Explosionmancer.