Okay, so I recently came up with a character concept revolving around a tech-priest that undergoes the Rite of Duplessence and finds that his new companion has been tainted by chaos as a latent psyker. I'm sort of going for a Jekyll/Hyde type thing and was planning on mechanically saying that the character is a wyrdling (tainted origin path and witch-born (I think?) lineage, starting Psy Rating 3) who doesn't actually realize their divinatory powers are more than luck, good guessing, etc. sort of like the force-sensitive before they become jedi. Eventually, he'd pick up Awakened Psyker and Acolyte of Abraxas as he discovered and made use of his powers.

So the rules question here is that the Rite of Duplessence says that the secondary brain can take any advances off the Explorator's advance chart. If I take alternate career ranks, the brain should be able to buy off those as well. So if I take Awakened Psyker, I could take say the Divination discipline and buy four more powers from that, and then the binary cortex could take, say, Telepathy and buy its own four powers, yes? Since it doesn't have the origin path bonuses I do, it should get a psy rating of 1 by RAW while I have a psy rating of 4 (both going up by one when I take Acolyte of Abraxas)? Further, with the Unhallowed Discoveries of the AoA, the brain can buy its own set, but if it rolls perils of the warp, I assume that I would take the energy damage as specified, while it takes the Corruption points?

Okay, its been a few days, and 50ish views. Is the lack of replies due to general disinterest in the topic or lack of a definite answer, or what?

As far as I understand it the Acolyte of Abraxas doesn't actually add anything to psy rating without the unhallowed discovery and the psy rating bonus from this talent are not the awakening of the Explorator's mind but a result of the psychically charged xenos artefacts.

Given that the career specifically states the psy rating and powers are removed if the artefacts are ever removed I would assume that a brain added with the right of duplessence doesn't gain any of these powers as it only has access to the implants specifically installed in itself.

I like the Jekyl and Hyde idea but I think that it is better as an heretical NPC who attempted to duplicate the right of duplessence without the right resources and had to use xenos tech to do the job. It seems like something more deserving of a house rule or custom situation rather than something that could happen with the right of duplessence as it stands.

By RAW, I can't think of anything that would prevent what you suggest, but from a fluff-perspective and a GM, there's no way in hell this wouldn't result in all kinds of hellfare.

By RAW, I can't think of anything that would prevent what you suggest, but from a fluff-perspective and a GM, there's no way in hell this wouldn't result in all kinds of hellfare.

Yea, I was scratching my head looking at all the rules and was like "this could work...... but why????"

By RAW, I can't think of anything that would prevent what you suggest, but from a fluff-perspective and a GM, there's no way in hell this wouldn't result in all kinds of hellfare.

My RAW interpretation is legal, though?

The intention here isn't powergaming, so I fully anticipate plenty of heat from the authorities/party (since what it amounts to is harboring a chaos cultist inside your own mind). Honestly, were I the GM, I'm not sure that I would give "control" of the binary cortex to the player.

By RAW, I can't think of anything that would prevent what you suggest, but from a fluff-perspective and a GM, there's no way in hell this wouldn't result in all kinds of hellfare.

My RAW interpretation is legal, though?

The intention here isn't powergaming, so I fully anticipate plenty of heat from the authorities/party (since what it amounts to is harboring a chaos cultist inside your own mind). Honestly, were I the GM, I'm not sure that I would give "control" of the binary cortex to the player.

Potentially legal. Fluff wise as the Acolyte of Abraxas career gives the enemy and rival traits for the Adeptus Mechanicus I think they'd do what they could to remove the binary cortex (assuming they thought it was untainted) once the PC became an Acolyte of Abraxas.

With the binary cortex trait the wording for the secondary brain's abilities is:

The brain starts with a number of Intelligence-based Skills, chosen from those currently available on the Explorer’s Advance Scheme (so, if the Explorer is a Rank 4 Explorator, the other brain in the Binary Cortex can buy any skills from ranks 1-4 of the Explorator advance scheme), equal to his Intelligence Bonus, and all are considered to be Trained Skills, Basic or Advanced depending on the skill’s normal type.

Given the wording specifically says skills not talents or traits I'd say the brain would not be able to start with things like a Psy rating which is a trait.

Now the brain could potentially gain a Psy rating with this text.

Experience may be spent on skills, talents and advances for the second brain, all of which are taken from the Explorer’s present advance scheme but which must be purchased with its own experience, which it gains at half the rate the Explorer does. Talents may only be purchased for the second brain if the effects of those talents are completely and utterly mental in nature, and the second brain cannot meet the prerequisites for any talent if they include any characteristic the second brain does not possess.

As the only requirement here is WP 35 it is plausible that the brain could gain this.

Now the Acolyte of Abraxas psy rating boost come from xenos artefacts the wording specifically says:

By integrating psychically charged xenos artefacts into his bionic form through arcane processes, an Acolyte of Abraxas can channel the power of the artefact through his mind, performing feats much like those of true psykers by virtue of their tainted relics

With the Right of Duplessence there is this text:

Similarly, bionics and implants may be added to the second brain only if they apply specifically to the brain—there’s no point fitting a binary cortex with a bionic arm, but a Cortex Implant is entirely appropriate.

In my mind this means that you'd have to impant artefacts directly into the secondary brain for it to be able to use them. Not impossible but I think I wouldn't let it go as high as three. I'd also be tempted to have the brain become an NPC at that point as it may not want to have heretical technology loaded inot it. I assume only the most loyal and dedicated members of the Ad Mech become brains for the Binary Cortex upgrade.

Also I might be looking in the wrong place but I think the only lineage that gives you access to a Psy rating is Perilous Choice and that only gives you a rating of 1 so with Awakened Psyker you'll get to 2 and then the Acolyte career maxes you out at five. If you're going with tainted to get that extra Psy point then it would have to be rolled as the Perilous Choice lineage costs 500 xp (IE all the standard starting xp) so you won't have the 200 xp needed to choose the mutation. On the other hand the Wyrdling mutation gives you a psy rating of 2 so just taking that is better than the lineage anyway.

Perilous Choice is indeed the one I meant. And I forgot about starting xp, since the game I'm in right now is rank 2. Whoops