With the changes to preferred enemy, there has been buzz for almost 2 months about voluntarily killing an Ethereal, otherwise known as "Ethereal Bombing". But do the perks of PE really outweigh both the 50 points and the chance that our units will run off the board? With a friend pointing out that as much as I love Math Hammer I rarely ever post anything on my blog that looks anything like my notebook, so I figured I would let you into the madness known as my view of Math Hammer.
Background
I'd just like to start out by stating that Ethereal Bombing is not supported by fluff. The Tau hold the worth of a single Ethereal to be worth countless other members of the Empire. This is supported by the storyline surrounding the PS2 game Fire Warrior, and fluff in the new Dark Eldar Codex that show that the Tau didn;t really think twice about sacrificing 777 members of the four mainstream castes, but when asked to surrender 77 Ethereals they were ready to go to war. But who honestly likes the Ethereal caste as a Tau player. Watch how they prance around in Dawn of War like they are channeling some kind of psychic power, despite the fact that they have no registry in the warp. Read how they refuse to wear any kind of practical armor in the codex. Read how they keep secrets from the other castes and how they instruct Earth Caste members to sterilize and build mind controlling devices to deal with other races. Not to mention Farsight reached awesome status when he said bye-bye to Ethereal rule. I personally play my Tau to have attitudes towards Ethereals like catachan have towards commisars. They don't openly hate them, but you rarely see them on the table because they always seem to come across unfortunate accidents. What better way to represent this on the table than a lone Ethereal running by himself several inches in front of the enemy. "The Price of Failure", is not a new mechanic to the Tau who have always had to perform a break test if an Ethereal died. To put it simply, every Tau unit (this doesn't include Kroot, vehicles, drones, Vespid, or any allies) that is on the table must take a break test before the Tau movement phase. All units that take this test receive PE. PE used to mean that your unit would automatically hit on a 3+ in close combat back in 4th edition. This changed to" re-roll all failed to hits in close combat" during 5th edition. Now in 6th edition this has changed so that if at least one model in a unit has PE the whole unit re-rolls any rolls of 1 for any to hits and any to wounds against the specified enemy. But what does this really mean for us Tau?
Mathhammer
One thing to understand is that this game has a number of variables that make it all but impossible to explain every scenario within a blog post of reasonable length, so for the sake of sanity i'll be going over some of the most common scenarios. Preferred enemy affects only to hits and to wounds so i'll be showing how those two stats have changed.
A quick guide to Math Hammer
If you already know how Math Hammer works please skip to the next section
The effectiveness of a Kroot firing back and forth at a Space Marine at 24 inches in open terrain verses cover.
-The Space Marine(15 pts) firing at the Kroot(7 pts)
needs 3+ to hit, 3+ to wound, allows no save, with 15 points invested into firing at a 7 point target, this translates to:
(2/3) * (2/3) * (1/1) * (7/15) = 28/135 = .2074074074...
The Kroot (7pts) firing at the Space Marine(15pts)
needs 4+ to hit, 4+ to wounds, needs a 2- for the save, and invests 7 points against the Space Marines 15, this translates to:
(1/2) * (1/2) * (1/3) * (15/7) = 5/28 = .17857142857142...
Notice how the Kroot are marginally weaker than the Space Marine when they are firing at each other in the open
Now let's use the same scenario but place both of them in the average 5+ cover
The space Marine goes first
needs a 3+ to hit, 3+ to wound, 4- to avoid the cover save, and targets a 7 point model with 15 points invested:
(2/3) * (2/3) * (2/3) * (7/15) = 56/405 = .1382716...
and the kroot, note how nothing changes from the Kroots last example as the Space Marines 3+ Armor trumps the 5+ cover save:
4+ to hit, 4+ to wound, 2- to avoid the save, targeting a 15 point model with 7 points invested.
(1/2) * (1/2) * (1/3) * (15/7) = 5/28 = .17857142857142...
This shows that the Space marines have a return of about 14% per point invested while firing at a Kroot in 5+ cover while the kroot have a return of roughly 18% per point invested when firing at a squad of Space Marines, this is assuming that averages will eventually balance out.
Against targets with Toughness 4
The reason I show Toughness 4 is that it's the most common toughness seen on the table followed by toughnesses 3 and 5, then followed by toughness 6, then 8.
For our examples i'll use an unbuffed fire warrior both shooting and in the assault. For shooting i'll show how Preferred Enemy and Markerlights will not effect the overall change in effectiveness between a Fire Warrior with PE and without.
While shooting at T4 the Fire Warrior without PE needs 4+ to hit, and 3+ to wound, this translates to
(1/2) * (2/3) = 1/3 = .3333...
The Fire Warrior with PE needs 4+ to hit, re-rolling 1's, and 3+ to wound rerolling 1's, this translates to
{(1/2) + [(1/6)*(1/2)]} * {(2/3) + [(1/6)*(2/3)]} = (7/12) * (7/9) = 49/108 = .45307307...
to figure the % increase in effectiveness we subtract the unbuffed Tau effectiveness from the firewarrior with PE, then we take the result and divide it by the effectiveness of unbuffed fire warrior
[(49/108) - (1/3)]/(1/3) = (13/108)/(1/3) = .361111... = 36.11%
What does this mean? Tau Fire Warriors with PE will be killing at least 4 space marines for every 3 that Fire Warriors without PE kill.
If you compare markerlight hits with these fire warriors you'll see a PE FW with a markerlight to boost his BS by one when compared to an unbuffed Fire Warrior with +1 BS is still 36.11% effective, the same goes for fighting with 2 markerlights, against toughness 3,5, and 6, and against the same toughness values in an assault. It seems Fire Warriors with PE have and increased killing effectiveness of 36.11% when firing at anything toughness 8 or below, and assaulting anything with toughness 6 or less in an assault. So how much more effective are they when firing at vehicles?
Knowing that Fire Warriors don't have a chance to roll to wounds against vehicles all we get to compare is the to hit.
4+ to hit = 1/2 = 50%
4+ re-rolling 1's = 7/12 = 58.333%
(1/12)/(1/2) = 1/6 = 16.67% increase in effectiveness when firing at vehicles
The same can be said for Assaulting armor with EMP grenades.
Now that we know we know the increased effectiveness of fire warriors what about suits with twin-linked weapons?
Using out logic we know that a twin-linked weapon will always take precedence to hit as, all failed to hits are re-rolled not just 1's. This means we Just compare the to wound rolls lets just assume we wound on a 2+
5/6 without PE
35/36 with PE
(5/36)/(5/6) = 1/6 = 16.67%
As we know toughness does not affect the effectiveness of our PE so this will be the increase of effectiveness of a twin-linked weapon, assuming we are firing at something we can wound. We also see that PE has no effect on twin-linked weapons when firing at vehicles.
meaning that if we supposedly had an all fire warrior list (I know it's impossible), at 750 points. We trade 5 fire warriors for an Ethereal dropping the overall killing potential of the army by 6.67%. We must also consider the chance that our fire warriors run away instead of being able to use PE. The Fire Warriors have a 27.77% chance of running away at leadership 8. Armies that use firing lines in the deployment zone will have a pretty good chance that they run off the board. these means that at a drop of 6.67% and adding it to the chance of running away 37.77%. We get an overall drop of effectiveness of 34.44% vs. the increase of effectiveness vs. infantry at 36.11% and 16.66% versus vehicles. Though this is an extreme example you also need to take into consideration this How close to the table edge do you keep your broadsides and remember the broadsides will receive a 0% boost against armor, a 16.67% increase against anything with a toughness value, but have a 27.77% chance of running away. So if you use twin-linked weapons you'll receive a 16.67% boost when firing at something with a toughness value (unless you use Twin-linked, flamers in which case you get a 0% boost) or Assaulting a vehicle, no bonuses when firing at a vehicle, and a 36.11% boost in an assault. Take into consideration anything with Ld 10 only has a 1/12 chance of fleeing.
Bomb one hide the other
One strategy I took into consideration while thinking about suicidal Ethereals is killing one and having another Ethereal on the table allowing all units that have to take a test the chance to re-roll failed leadership tests, meaning after the Ethereal dies, your units go from having a 27.77% chance of running to having less than an 8% chance of running. Meaning that if you are running a 2000 point army with nothing but suit without twinlinked, blast or template weapons, and fire warriors, you are maximizing your your effectiveness boost granted by PE.
Breaking "Price of Failure"
When we think about this rule we really need to ask the question, what is a Tau unit. Is it simply a squad that is normally Tau? Do Sniper Drone Spotters test? If not then Commanders with drone controllers don't have to test. Does an Eldar Pathfinder squad with a Tau character attached to it count as a Tau unit? If not then the character doesn't have to roll a leadership test when the Ethereal dies? How about vice-versa? If a Firewarrior squad is joined by a non Tau character I.E. Anghkor Prok, or a Farseer still count as a Tau unit. If so take a close look at the rules for independent characters. If an effect takes place while an independent character is part of a unit the effect carries over when the independent character leaves meaning that character still has PE after it leaves the unit and the unit still has PE as well. PE is also transferable meaning that if a character with PE joins a unit that unit also gains PE. The Farseer leaves the Fire Warriors and joins a kroot squad granting the kroot PE.
So before you start a battle with the Ethereal Bomb Tactic ask these questions to keep from fighting with your opponent later
1. What is a Tau Unit
2. Do Tau Characters make other units count as Tau units when joined
3. Do Tau still count as Tau if joined by a character of another race?
Since I have figured out the benefits of PE while using Price of Failure, I really don't want to give up my twin-linked flamers, broadsides, allies, reserves, vehicles, or non Tau units in the codex, but I wouldn't mind a battle here or there where I just confuse my enemy with a Suicidal charging Ethereal while I transfer PE from unit to unit with my Farseer.
What do you think?
Let me know, personally I find the advantages to be almost nil for what you have to give up.
