Blood Lord

These foes use the

Frenzy skill, which ramps up their attack speed and makes disengaging difficult. A character surrounded by an elite pack of Blood Lords can easily find itself overwhelmed.

While they are not Immune to Cold, Death Lords (found in the

Worldstone Keep Level 3 and

Throne of Destruction) cannot be frozen or slowed by Chilling effects.

From the

Arreat Summit:

Blood Lords use

Frenzy.

Blood Lords have a chance to deal Cold damage.
Hell Lords have a chance to deal Lightning and Fire damage.

These enemies can prove particularly tough and troublesome to deal with, having possibly the highest resistances to every single damage type vs almost any other enemy in the game (someone correct me if I'm wrong there), while also having the distinction of being an enemy that is not a Demon or Undead.

This can prove very problematic if you're a physical damage character and you happen to run into an elite pack with the Stone Skin modifier. Adding 50% physical damage resist to their base which is always a minimum of 66-75% means you won't be able to break their immunity with a Decrep proc (or even with an Amp Damage proc in some cases) - and their non-Demon/Undead status makes other methods of breaking immunities that work against Demons/Undead useless (Lawbringer/

Sanctuary Aura,

Holy Bolt, etc). If you're a FoH paladin running into an elite pack with Stone Skin + lightning immunity, you might be kinda screwed here.

Running into an elite pack with a combination of Stone Skin, Might/

Fanaticism Aura, Mana Burn, Cursed, etc may be more than enough reason to consider skipping past them in some cases.