Boss mods

Today I want to talk about boss mods, these are the random powers that randomly generated champions and rare bosses get.

In Normal difficulty a random champion or rare gets at least one
In Nightmare difficulty a random champion or rare gets at least two
In Hell difficulty a random champion or rare gets at least three
In Inferno difficulty a random champion or rare gets at least four.

This nasty rare from Diablo 2 has 5 boss mods.

We have some video of a fight against an Inferno level champion pack in the You Will Die video Blizzard showed at Blizzcon and uploaded to their site last week.

The interaction of the boss mods, how well they synergise with each other, plays a big factor in determining how dangerous they are. Multiple Shots and Lightning Enchanted, the famous and dreaded MSLE from Diablo 2, worked particularly well together making a boss that had those two properties unusually dangerous.

I think we can explain why the Blizzard staff found this Diablo 3 champion pack so difficult by looking at the mods. They are fighting champions that are Electrified Vortex Desecrator Teleporter. Usually in Diablo games most characters protect themselves by keeping at range. Vortex allows the boss to pull players to it. Teleporter drops the boss to a random place. So imagine trying to control a fight where the bosses can pick a target and yank him close or may randomly teleport to him. It's the fact that these champions have both those abilities that makes them particularly dangerous - this looks like a very difficult pack to keep range on.

Here are some of the boss properties we know about. Fluddastud1 has very kindly filmed some of these mods. Credit is also due to the excellent wiki page at Diablowiki.net.

Arcane Enchanted.

In the beta this originally allowed the boss to drop arcane hydras which were noted by several Beta playtesters as the most dangerous thing they saw in Beta. Watch the unfortunate Force get killed by this boss mod at 18.15 in his Barbarian Let's Play walkthrough part 2. The Arcane enchanted mob is at the back throwing those purple balls. It's since been toned down.

It adds Arcane damage to boss attacks. It probably also increases Arcane resistance.

See it here. In this case the mod takes the form of dodgable laser beams.

Ballista

Increases the size and damage of ranged projectiles.


Desecration

I don't think anyone knows what this does outside of Blizzard. My guess from seeing it in the You Will Die is that it adds damage, possibly synergising with Electrified.


Electrified

Bosses emit sparks when struck and add lightning damage to attacks. They also have higher resistance to Lightning attacks. In Diablo 2 this mod was one of the most dangerous in combinations because the sparks emitted were considered ranged attacks and picked up bonuses from other boss mods. So Multi shot and Fire enchanted considerably increased the damage of the sparks emitted. It may work the same way in Diablo 3.

I suspect that it is this mod that did the bulk of the damage that killed the Blizzard team in You Will Die. Possibly enhanced by the Desecration mod.

See it here.


Fast

Boss and its minions move a lot faster. This is a powerful multiplier for any boss that hits hard. Also because of the way the game calculates weapon damage for the purposes of determining spell and ability damage this is possibly also directly a damage boost. (Hat tip to Nunc and the Armada theorycrafters for the research, speculation is my own).


Frozen

Adds cold damage to the boss's attacks, adds cold resistance. Damage chills players causing them to move and attack slower (and as we've seen attack speed is factored into ability damage). It also sometimes freezes players (can't move or cast). In addition when they die they Frost Nova freezing players solid.

Fluddastud1 shows it in detail here.


Knockback

Boss sometimes causes the player to be thrown back on hit.

See it here.

Linked

The pack shares a health pool. You can't kill any of them until you've got the entire pack down low on life. A strong defensive ability that negates the common player tactic of pulling one mob away and killing it off alone.


Magical

Possibly no longer in the game, seen in 2009 play testing. Not known what it does/did.



Mirrored

The bosses and champions can create duplicates of themselves. These duplicates gain all the abilities of the original but have half the life. This is a nasty mod on a tough boss because it increases the damage, spreads the coverage of the area you're fighting in and also increases the hit points you need to destroy in order to win the fight.



Molten

Adds fire damage to attack and increases fire resistance. It also causes fires to appear on the ground damaging people who stand in them. Do not stand in fire!


See it here.

Mortar

Boss fires explosive ranged objects. This in theory is designed to penalise ranged characters. It may be possible to evade the fire though if at long range. It may also be possible that the ability has a minimum range and you can get inside the minimum range and so negate the damage.

See it here.


Multishot

Improves ranged damage.


Mythical
Seen several times during Blizzcon 2009 play testing, but its effect wasn't apparent to any of the players.


Nightmarish

A new mod added in the most recent patch. Hit causes player to flee. This seems extremely dangerous to melee characters. The only real counter (other than keeping distance) is cc reduction gear and passives along with high defensive stats.



Plagued

Adds poison damage and increases poison resist. They have a cloud of poison around their feet. When these mobs die they release a cloud of poisonous gas.

See it here.



Powerful


Bonus to melee damage for the whole pack.



Stoneskin


Bonus to physical resist.



Teleporter


Boss teleports around, jumping once every 6 seconds or so to a random place.

See it here.



Vampirific

Boss heals itself by doing damage. Reportedly very high, this can make bosses virtually impossible to kill. Doing the maths this ability will be strongest when players are under-geared, tailing off rapidly once players gear up since both the players' defensive stats and their offensive stats reduce the effectiveness of this mod as they increase.



Vortex


Bosses and champions with this mod can pull players to them. Nasty for ranged characters but probably a non-issue for melee.






Conclusion


Boss mods make a huge difference to a fight. Certain mods are insignificant against some teams - a Barb and a Monk would be delighted to see Vortex.

It seems to me that the odds are still stacked against melee.

Melee unfriendly:

Arcane enchanted (laser beam version)
Electrified
Frozen
Knockback
Molten
Nightmarish
Plagued
Powerful
Stoneskin
Teleporter
Vampirific

Ranged unfriendly

Fast
Mortar (at least in theory, Diablowiki.net argues that it's trivial for ranged characters to avoid but hits melee when they have to close in).
Teleporter
Vortex

And of course a mob that melee attacks is innately more unfriendly to melee than ranged because you have to go up close and trade blows.

Cherry-picking will be highly possible and may even be essential at the start of Inferno difficulty. A Fast Powerful Vampirific boss for instance would probably just deal out too much damage and leech so much back as life that an under-geared group would never kill it. Could never kill it, not mathematically possible.