I am wondering about this one. I have a character which has taken this, however i'm wondering what the benefit would be of having the secondary brain take a +10 or +20 in a skill? It could get Tech Use +20 for example, but the rule explanation says that the secondary brain grants the bonusses of someone helping out. In which case it seems more logical to not get a +10 or +20 on any given skill as it doesn't make a difference for the bonus the main brain gets?

Or am i missing something here?

For assistance it doesn't help. But there will be times when the secondary brain makes a test on its own (for example, a lore test to recall a specific fact*), which is where the +10/+20 will help.

*A test where I will not allow assistance. But even if the gm does, rolling twice will often give a better chance than a +10 to a single test. Some quick calculations tell me that, if you have two characters with identical chances of success, the break-even point is when they have an 11.27% chance. Above that, having each character roll separately has a higher chance of at least one of them passing than one assisting the other. Which means the +10/+20 advances do have value.

Though this is only for a simple success. Accounting for DOS will be more difficult.

Badlapje said:

Depends on the skills. If the secondary brain is using the same skill as the character, then it grants the bonuses of assisting, yes... but if the secondary brain has skills that the character doesn't, it can test against them normally and then confer the information/benefits of that successful tests to the character.

Given that the secondary brain gains less XP than the character, it makes sense not to overspecialise on skills that the character possesses, instead using it to bolster the character's skills and broaden his effective range of knowledge by picking skills he doesn't have.

Another thing to note: The starting Int on the second brain is 2d10+40, including two int advances. Meaning the base int is 2d10+30

The starting int from most worlds is 2d10+25, so it isn't hard to see the second brain having a higher int that the PC. So the second brain can sometimes have the better target value, especially if it takes the +10/+20

While the second brain gets less XP to spend, it also has less to spend that XP on.

So the better question may be: What else do you have to spend XP on ?

N0-1_H3r3 said:

I've been thinking about that, it would make sense except that the secondary brain only has access to information via the senses of the primary brain. In other words: it's not logical to have it learn eg. High Gothic unless the primary brain is learning it at the same time. For Lore skills this would be even more the case. One could solve that by adding two eyes to the back of the head which link to the secondary brain (and which - if the secondary brain allows for it - the primary brain gets images from), but this is explicitly forbidden by the Binary Cortex Trait description.

Might be that i could get around that by using a servo skull and a MIU though. That would be interesting, though that would logically also mean that the initiative penalty get's reduced some.

Bilateralrope said:

I believe it is assumed the secondary brain is from a forge world which is why it gets the +5 to Int compared to the starting intelligence. If you'd build up the secondary brain from scratch you could viably arrive at a higher starting score.

I believe N0-1_H3r3 already answered that question. Skills which the primary brain does not possess would be a good investment. With the problem i described above taken into account however. Logically speaking they would all be elite advances, but once the MIU is gained it might be feasible to convince a GM to allow a secondary brain to take a different career then the one the primary takes (Xenographer for example).

I've been thinking about that, it would make sense except that the secondary brain only has access to information via the senses of the primary brain. In other words: it's not logical to have it learn eg. High Gothic unless the primary brain is learning it at the same time. For Lore skills this would be even more the case. One could solve that by adding two eyes to the back of the head which link to the secondary brain (and which - if the secondary brain allows for it - the primary brain gets images from), but this is explicitly forbidden by the Binary Cortex Trait description.

I'd assume the techpriest would be capable of downloading information into his internal memory by hooking appropriate datasbases up to his electoo inductor. At that point, the secondary brain could read them at its leisure and thus develop its skills.

not really as the information goes to the primary brain which still needs to make a conscious effort to relay the info to the secondary brain.

Binary Cortex is just another item taken for the old Inquisitor game that was poorly thought out in it's transfer over. It should have been just a +5 maybe +10 to a set of skills with a 10% chance that the secondary brains slows you down for a -5 skill test.

Wel, here's me who loves the idea and how it's been worked out. The only thing that's i dislike is the restriction on bionics for the second brain. But then that's easily houseruled and i can get the thinking behind it (or at least i can see a possible reasoning for it, dunno if that's what the author thought).

Thx for the helpful info though!

myth835 said:

It's an entire second brain for the character, with its own distinct personality and knowledge (and that's exactly what it was in Inquisitor as well... where it was far more than just "+5, maybe +10" to a few tests, but a +70 bonus to the character's Sagacity... it's not just a simple bionic implant.

When i wrote the rules for it, I looked at the background given in the Specialist Games article it was added in, and devised something based on that. That's the way I've written all the rules I've produced over the years, both in my own time and officially.

Badlapje said:

My thoughts were that the secondary brain exists solely for intellectual matters (having discarded its original flesh), and consequently shouldn't be burdened with anything that links it to the outside world - that's why it became a disembodied brain in the first place.

N0-1_H3r3N0-1_H3r3NOno

N0-1_H3r3, yes it appeared to have a large stat increase and bonus to it in Inquisitor, but over all it was a very low impact on the game .

No were near the impact for DH, RT,and DW. Check around on some of the play by post forums you might be suprised by how many techpriest, magos, and techmarines are stuffed with the binary cortexs.

Markus, "It is not uncommon for two Techpriests working on the same mysteries to coincide so entirely in their thinking that decide to link up in a very literal sense. Both brains are linked to a single body so that they can work more efficiently together" -Thorpe

Wouldn't mean Techpriest A and B both have forbidden lore warp, not one has forbidden lore mutants and the other xenos?

N0-1_H3r3 said:

I love you running around on these forums You seem to be writing all my favourite content AND you reply to questions and offer your reasoning

My idea was that the restriction was put in place to avoid the secondary brain doing something the primary didn't want (and could potentially be dangerous assuming the secondary gets corrupted for instance) & also from a game-technical perspective to avoid it being used by one player to play two characters as opposed to the one which everyone else gets to play.

Your explanation makes more sense though, it fits in nice with the reasoning behind being disembodied. Still having some kind of link to the world in order to study those things it wants to study also makes sense to me, as otherwise the secondary brain is extremely limited to whatever the primary wants to share. I reckon i'll go with a middleground of having it control a servoskull through a MIU but only rarely so and nearly exclusively for the purposes of studying whatever it's interested in at that moment. Maybe have a little surgery to allow the use of the electoo inductor to download info directly into the secondary brain if desired in order to decrease the need for the use of that servo-skull further still.

Badlapje said:

Aye, it's useful having one of the guys who writes this stuff posting why he went with what he did

myth835 said:

Of course not - Inquisitor was, afterall, still a wargame, and consequently intellectual pursuits are of a far lesser concern to the average game of Inquisitor than to a Dark Heresy, Rogue Trader or Deathwatch campaign.

myth835 said:

Many lores can all contain elements relevant to a single field of study - afterall, if a Tech-Priest was going to only study one thing, they'd surely only ever need a single Lore skill, rather than training in several.

Beyond that, there is another way to use a Binary Cortex - each brain engages in research seperately; the second brain can devote all of its time to researching something (such as using the Investigation rules) given that it has no other concerns, while the character can get on with other things, including researching something else entirely. It alternatively gives you two chances to succeed at the same test - each brain makes separate tests for the same thing.

In essence, it's two characters, one of whom has no physical body, with all the advantages and disadvantages that come with that notion.