Blood Golem Mechanics

Diablo II Expansion, patch 1.09d
By Tommi Gustafsson

Necromancer's Blood Golem has a powerful life steal ability, which functions with Iron Maiden curse and Thorns aura (available from Act 2 combat mercenary aura in nightmare difficulty). Combined with them, a blood golem can steal very high amounts of life, making it immune to physical melee damage and at the same time providing staggering amounts of healing to the necromancer. This article explains how the game handles the blood golem mechanics and how the interaction with Thorns and Iron Maiden works.

1. Blood Golem Abilities

A blood golem has three special abilities: life steal, damage sharing, and healing transfer.

1.1 Life steal

A blood golem steals life from monsters it hits. It functions as follows:

• The blood golem must score a hit to steal life.
• Life steal is proportional to the physical damage done by the blood golem.
• The life steal percentage depends on the level of the golem (86% at slvl 1, 138% at slvl 20).
• Life stolen by the blood golem is not reduced from the target.
• 70% of life stolen is added to the golem's life amount and 30% of life stolen is given to the necromancer.

For example, if a blood golem has 126% life steal and it deals 50 points of damage, it will steal 63 life. 44.1 life is added to the golem's life total and 18.9 life goes to the necromancer. Additionally, the blood golem's life steal uses the following mechanics:

• If the golem reaches full health through life steal, the remainder of the stolen life overflows to the necromancer.
• If the necromancer reaches full health, the remaining healing goes to the golem.
• The blood golem's damage and the amount of life stolen are reduced by target's physical resistance. Thus, the blood golem cannot steal life from monsters immune to physical damage.
• The blood golem cannot deal more damage than its target has life left. Therefore, its life leech is capped at life steal % x target's life amount.

Amplify Damage curse helps a blood golem to do more damage and steal more life by reducing monsters' physical resistance by 100%.

1.2 Damage sharing

A blood golem shares damage it receives with the necromancer. Damage sharing has the following properties:

• The blood golem receives 90% of the damage dealt to it, and 10% of the damage goes to the necromancer. The sharing takes place after all damage modification effects of the golem have been applied.
• The damage shared by the blood golem is straightly reduced from the necromancer's life amount, and hence it bypasses all damage modification effects of the necromancer, such as Bone Armor.
• The necromancer cannot be killed due to the shared damage, only reduced to 1 life.

One should also note that:

• Golems take extra damage from act end bosses (3 times normal damage from Act I-IV bosses; 4 times normal damage from Baal).
• Recasting a blood golem prevents the golem from dying, but it does not affect damage shared. Recasting is useful if you want to be sure that the blood golem is continuously stealing life.

1.3 Healing transfer

A blood golem gets part of healing the necromancer receives. Unless at full health, the blood golem receives 25% of healing the necromancer is subjected to. The necromancer gets 75% of the healing.

2. Interaction with Thorns and Iron Maiden

The life steal ability of a blood golem functions also when monsters attacking it receive damage from Thorns aura or Iron Maiden curse (or Spirit of the Barbs).

2.1 Thorns and Iron Maiden Mechanics

See my article on Thorns and Iron Maiden mechanics.

2.2 Blood Golem with Thorns and Iron Maiden

Damage from Thorns or Iron Maiden is counted as an attack by the blood golem, and therefore it steals life equal to Final Returned Damage x Life Steal Percentage (final returned damage is the damage after all modification effects, i.e. the damage actually dealt to the attacker). Because Iron Maiden and Thorns deal very high amounts of damage, the blood golem also leeches huge amounts of life via them. Blood golem has 0% physical resistance, and thus it does not reduce damage dealt to it. Monsters in the hell difficulty, on the other hand, have 50% physical resistance.

A blood golem becomes "immune" to physical melee damage when it steals more life than monsters deal damage to it. To achieve this state in the hell difficulty, one needs either Iron Maiden of level 2 or higher (225%+ damage returned) or Thorns aura of any level (250%+ damage returned). Such a blood golem can take damage endlessly and it provides a continues flow of healing.

2.3 Should I use Thorns or Iron Maiden with a blood golem?

The benefits of Thorns and Iron Maiden are so great that one should always use one of them with a blood golem. Amplify Damage also helps the golem to steal more life, plus it increases Thorns damage.

3. Related Questions

3.1 How many points should I put into Golem Mastery, if I use a Blood Golem?

A blood golem does not need lots of life, because it steals plenty of it from attacking monsters. The greatest problem with it arises when the golem is subjected to ranged or elemental attacks. In that case, it cannot leech back life through Iron Maiden or Thorns, which makes it prone to die. A necromancer using a blood golem has to be very careful that a loss of a blood golem does not reduce him to such low life levels that he could be killed easily.

A blood golem has 637 life in hell difficulty. This amount is modified by Golem Mastery. The maximum number of damage that may be shared to the necromancer can be calculated by dividing the blood golem's life total by 9. This case happens when a full health blood golem is killed before it can steal any life. The figures in hell difficulty are the following:

Golem Mastery Level	Blood Golem Life Total (in hell difficulty)	Necromancer Life Lost Upon Golem Death
0	637	71
1	764	85
11	2038	227
20	3185	354
30	4459	496

Because necromancers have usually a high number of bonuses to skills, a minimum level of golem mastery may be 10 or so. With level 11 Golem Mastery, the necromancer loses 227 life, if his blood golem is killed, which is quite high for many necromancers. Therefore, if you use mainly a blood golem, it is recommendable that:

• If your necromancer has high skill bonuses or low life total, put no skill points into Golem Mastery.
• If your necromancer has low skill bonuses or high amounts of life, put 1 skill point into Golem Mastery.

Note that you are not able to put skill points into Summon Resist, if you don't put skill points into Golem Mastery. It is usually not a big problem, though, because you should not use a blood golem against monsters with elemental attacks and revives retain their original resistances.

4. Acknowledgements

BillyM for several good suggestions and for initially pointing out that the blood golem uses different mechanics than what I thought first. Thanks to him also for pointing out that it may be counterproductive to increase golem mastery with the blood golem.
Chippydip for a very informative Diablo 2 skill information site.
Jarulf for reporting how the blood golem's life leech is handled in the game code.
Kikosemmek for clarifying how the blood golem's life steal works.
Kyrene for helping me to find out how the blood golem works.
Roland The Gunslinger for helping me to find out how the blood golem works.