I'd just like to start by getting out of the way that I am very new to Dark Heresy. As someone who has played 40K for the best part of eight years, I have a decent understanding of the setting, at least the simplified portrayal of it the table-top game gives you.

I suffer from chronic anxiety and thus have an innate problem with roleplaying that I naturally gravitate towards characters who tend to be very quiet or have suffered some kind of trauma that makes them uncomfortable when associating with others - I suppose it's a simple case of giving myself a starting point from which I can expect to be somewhat comfortable. One thing I've learned through experience is that I do far better when I have an extremely comprehensive understanding of my character, so that I can understand their particular viewpoint on events and how their history may affect their actions. I guess you could say that rather than taking my own thoughts and altering them to suit the character, I prefer to be able to decide how my character would act and tailor that to the present situation for the best effect. This makes me into something of an unyielding perfectionist; I want to be able to pre-empt how my character would react in a given circumstance because it'll make it far easier for me to adapt and plan than if I had to work in the spur of the moment. By playing a character in this manner, I make it far easier for me to actually make a contribution when the moment arises, rather than deliberating and re-writing a thought until the moment is lost.

For the game of Dark Heresy that I'm just about to join, I had originally intended to play a Death Cult Assassin. I had a character planned who essentially fell into the "cold sniper" niche, and had been hypno-indoctrinated from birth to believe that all of his orders came directly from the Emperor, thereby believing even the most insignificant failure was a slight that required an offering of self-flagellation before redemption could be attempted. The idea was to create a character who would eventually convince the other characters that they wanted to learn more about them and how they came to be in this state. I'd spent a decent amount of time simply deciding how the "Cult of the Emperor's Voice" would operate and how their politics would influence the mind of someone who had never been exposed to anything else. To that end, I had pre-programmed speeches written that would allow my character to espouse their own insignificance within the grand design of the Imperium, while affirming their absolute loyalty to it. The problem I realise this would create, something I previously had to evolve past in Dungeons and Dragons, is that it's quite possible for other players to take absolutely no interest in a quiet or brooding character and for it to simply result in them standing on the sidelines while everyone else has all the fun.

Disaster struck during the introductory session when it emerged that another player in our group, who I hadn't encountered before, had also decided to play a sniping-orientated Assassin and, being of the mindset that I am, I immediately arranged with the GM to sit out the session so that I could roll up another character. While I was a bit upset to see my work go to waste, that session made it apparent just how poorly my planned character would have meshed with the others in the group. It also didn't help that the GM had decided that the group would have a military briefing followed by a prolonged period in which characters could visit an armoury and generally swan around an Imperial base before we departed for our first mission. I had literally no idea how a character who wasn't used to those conditions would cope, or react to, the circumstances in which they had been placed. My immediate reaction was that upon leaving the briefing they would seek out a spot to meditate, to fill the 6-7 hours of inactivity, as a coping mechainism. Essentially I'd planned out a character who interested me and that I wanted to play but who would have been very little fun for anyone else to interact with, unless they enjoyed philosophy, and who would probably be very ill-suited for essentially any non-combat situations.

So, finally, this brings me to the focus of this topic: personalities for Tech Priests.

As you can infer, I've decided to play a Tech Priest but find myself at something of a loss for the sort of personality that the character would (should?) have. My character has the Forge World origin and, bar a Sanctionite who hasn't arrived yet, will likely be the group's main source of knowledge. Given that Tech Priests are notoriously poor at interacting with others not of the Cult Mechanicus, just how should I go about building my character's mindset?

For example:

Two of the other four characters (an Assassin and Scummer) are getting on like a house on fire. They've not shown much of a respect for protocol and literally took their leave and raced each other out of the Colonel's tent upon learning that they had been granted access to the armoury. They've disrespected engineers, human not Mechanicus, and have generally established themselves as being an ill disciplined lot with no regard for authority.

What would a Tech Priest's viewpoint be on this?

Would he consider it necessary to chastise them and if so, how should he go about doing it and how frequently?

Is it plausible for a Tech Priest, particularly one from a Forge World, to really have any social presence outside his fields of expertise and if so, how would he go about conveying opinions?

Essentially I'm looking for some help from people who have experience playing as, or with, Tech Priests regarding the typical voice of the character. What sort of balance between tech-minded human and protocol-based savant is best for the character and how can I go about creating an interesting personality that will make it relatively easy for me to gauge how and when I should speak?

Any help would be greatly appreciated.

Well, I don't know that there is a "best" personality for a Tech Priest. But if you want to go for the stereotypical TP, as portrayed in much of the literature, I'd say ... think the most hard-nosed, obnoxious Vulcans from Star Trek. That should give you a good starting point, or foundation.

Logic, the quest for knowledge, all wrapped up in mystical, secretive mumbo jumbo ... and tied specifically to all things related to the Holy Machine.

Other than that, it's just a matter of what you think would be fun to play. At lower ranks, tech priests have less augmetics, and are generally still mostly human in outlook (except that they worship machines). But as they progress and receive more of the Omissiah's blessings (augmetic enhancements), they typically become less human and more machine-like in outlook. But their are certainly many other ways to play TP's.

I apologize if that is not very helpful. But I'm afraid this is one of those dreaded "it depends" questions.

I have the impression that Tech-priests do not care much about authority and hierarchy outside that of the Adeptus Mechanicus structure itself of course. Sister Cat's mentionig of Spock is rather good, especially considering how his behaviour changed throughout his life. (Seven of Nine could also be a quite good example.) Young Tech-adepts tend to be introverted, logic and somehow monk-like (especially in their strict veneration of the Machine-God and any kind of machine as such); they furthermore act strictly according to dogma, always fully apply all machine-related rituals and try to suppress any kind of emotional/humanly behaviour (even though most are rather unaugmented so far). The older and more experienced Magi on the other hand tend to become more liberal (or even radical) as many realize that most of the dogmae and rituals they tended for decades are in fact not needed for most machines to function and many start to improvize and develop their own ways and approaces to problems, thereby becoming more akin to modern scientists (even if very conservative ones). They realize (as Spock did) that logic might be the beginning of all wisdom, but not its end. Many Magi tend to become kind of excentrical and even develop some sort of humanly quirks (humor, cynism, narcism) even though most are heavily augmented at this stage.

Many tech priests tend to be very secretive and are even known at times to put the possibility of letting admech secrets out above what others could consider larger or more immediate concerns. In many ways you might think of them like a cult, they have their own secret codes, means of greeting one another, philosophies, and insights.

The opinion about the relationship between the Emperor and the Omnisiah tend to vary between a belief they are one in the same, to the quiet disdain for superstitious corpse whorshipers who would do better to put their faith in the holy machine.

Not all of them have to be asocial, and in fact there is precedent in books of almost charming tech priests, but as a rule they tend to put off the impression that they are hiding something.

Often they are veracious consumers of knowledge mechanical, biological, psychological ... basically anything having to do with the sciences. (and there are different sects of the Machine cult who specialize in these varied subjects)

There is also the human self vs embrace of the machine element that every admech goes through. Some cannot wait to be rid of their soft and weak fleshy pieces, while others hold on to their humanity for as long as it remains reasonable. In fact, from what I gather the Biologis and some other branches never give up their flesh bodies to the extent your classic tech priest is portrayed as doing. (In the Calpurnai books the Tech Priest superior is a member of the Biologis and has only a few readily recognizable artificial enhancements)

As Cat said, part of distancing themselves from the human machine can reflect in a flatter affect - vulcan like - though I've seen a few certainly lose their tempers and become enraged in written works. Often they are quite arrogant, as they know things no one outside of the cult does and they are quite aware of it - and their special relationship with the Imperium. One rarely reads about tech priests laughing a great deal, or just hanging out with friends to have fun, though.

They don't stop to pray to every chrono or data slate, but generally acknowledge the divinity of such things in the way an animist acknowledges the spirits in rocks, trees, and animals. Larger, more complex, and older machines hold a particular awe for them, however, and should be treated with reverence.

And that's what I've got off the top of my head.

Trust Jack to expound so eloquently on my hurried - while at work - post.

What he said ... exactly.