First off, Luke Hill, Coady Rogers, Arnicia Taylor, and Anthony Evans, if for some reason you've finally taken my advice to set up accounts on this site and have found this topic, STOP READING NOW, OR IT'S NEGATIVE SPOT REPORTS AND CORRECTIONAL FOR ALL OF YOU.

now that i've gotten that out of the way, i'm starting up an Only War game with some friends starting in January, and I want to run a game revolving around a regiment that is the brainchild of a Radical Inquisitor and a Heretek Magos Biologis. basically, these two individuals want to find a way to bridge the gap between Astartes and Imperial guard, so they're funding/creating a regiment made up of what amounts to a whole bunch of Deathstrokes, minus the eye loss. the characters will be members of this shadow regiment, and sent to the spinward front as a field test, to see if they are a viable force. if they are, then the Inquisitor and Heretek will pitch the idea to their colleagues in a bid for more support. if not, then they'll be abandoned and branded heretics. as far as rules crunch goes, I want something like this:

• instead of the standard bonuses to attributes that other regiments get, this regiment (which i'm calling Blackwatch until i can find a more suitable name) will receive unnatural Strength (2) and Unnatural toughness (2)
• I want them to be jump infantry, similar to Assault Marines. Blackwatch has to be able to deploy rapidly. not only do they need to be able to get into battle quickly, they also need to be able to get out just as fast, in the event that they are in jeopardy of being overrun or, worse, they are potentially spotted by members of a standard regiment that would report their presence to High Command.
• Secrecy is a must for Blackwatch, and I want that to reflect in their drawbacks and tactics. not only are they basically heretics for just existing, there's so few of them that even one member lost is a blow from which Blackwatch never fully recovers. sneak attacks and ambushes are their baby, Protracted battles are never their friend.
• I want to add some instability to them, as a side effect of being the product of basically heretical gene manipulation. Mutation and/or insanity is a problem I want Blackwatch to have.

so the questions i have are:

• what kind of homeworld would befit a regiment like this? I was thinking either Feral worlds or Penal Colonies, since people going missing in those kinds of worlds tends to be overlooked by the Administratum.
• what would the stats and points cost look like on Jump Infantry?
• how would a regiment like this maintain secrecy? I was thinking having them be fleet based. they won't number more than ten thousand strong, so perhaps a light cruiser or two on the periphery of the Spinward Front would be kind of hard to find, and perfectly suitable to housing such a small unit.

Like the idea:

1) I would say either Void Born (illicit Magus Biologis ship) or an obscure forge world

2) I would say 1 point higher than Drop Troops (so 4) exchange Grav Chute for Jumppack (Grants Flyer 12)

3) Make them Voidborn and give them a Heavy Cruiser with several Drop Pod Launch Bays (Rogue Trader, Into the Storm)

I really like this idea, and I would recommend looking at the Gland Warrior from Rogue Trader, if you can, and perhaps the Genetor for some ideas.

1) This could be any, really, and I would say that it would depend largely on circumstance. Since we are in the end talking about real-life people, if you take them from regular regiments or worlds that contribute to regular regiments, you may have trouble hiding it up, not only because there's a paper trail, but also because in the end, these people may not want to go along with your plans, and many could very well have family "back home" that they hope to one day return to.

So my suggestion would be select individuals from Penal Worlds and the Schola Progenium, taking those that are without ties from the Penal Worlds and perhaps those that are otherwise underperforming within the Schola Progenium. The former will likely want to get away from the Penal World any way they can and not know any better when you do things to them, and the latter will likely be so indoctrinated and loyal that they don't care. Either way, aim for people without ties and previous loyalties and avoid paper trails.

2) Depends. Since you are aiming for stealth, I'm not so sure Jump Packs would be appropriate, and you might want to consider simply going for Drop Troops. Otherwise, just go for what Santiago said and bring at least one Stummer per soldier and give their gear Cameoline Coating. It's going to be expensive, though, but since you're the GM, you're the arbiter of what they can get.

3) Between a Magos and an Inquisitor, this should not be hard. Requisition a Navy (Heavy?) Cruiser, keep the Navy personnel and the Guard personnel separated (easier than you might think), throw a slew of Barracks and Drop Pod Launch Bays on it, and you're golden. Declare it a Vessel of the Inquisition and tell everyone to back off; go to the warzone and start kicking ass and taking names, and order anyone that is active in the deployment area to back off.

That's really all you can do. Make sure to have some back-and-forth between sector command. The Inquisitor is an independent agent of the Imperium, and aside from another Inquisitor showing up, you should have no problems with this, and there's no reason another Inquisitor should be showing up unless your soldiers start misbehaving something fierce.

As i was informed, Human-sized jet packs are hard to come by, and might need full power armor for power, as well as protecting the occupant from the exhaust, and what not (might also assist with drop pods). These all make for not to stealthy operatives. I'll say again, I wish IG could get official jump infantry

As for the rest, the Inquisitor can bring large deposits of handwavium with him, so lots of things are possible. Between him and a Magos, I'd say the only big worries are fighting something they can't handle. The rest has been said: get them from places where there won't be questions. Leave no evidence. Careful what they fight; a whole Waagh! of Orks is too much, and Orks always bring too much.

If you pull this off, I wish you and your group the best of luck, and hope you keep us in the loop, as to how it goes.

For what you want make sure you have a copy of "Hammer of the Emperor" for additional options.

With that in mind:

Homeworld: Frontier world: If this regiment comes from some backwater where the (Magos) set up shop (Gland manipulation and introduction is not Heretical. Since you are not actually trying to copy Astartes, you are not necessarily heretical.) would allow for secrecy.

Size: I would keep it fairly small to reflect the experimental nature. Perhaps Battalion size!

Transport: May I suggest a third partner? A Rogue Trader might be willing to become involved if he saw profit in it. A RT could operate in anything from a specially purposed transport to a Grand cruiser depending on his individual status and, He would absolutely understand the need to protect the secrecy of the project. Since He has no superiors to report to It's fairly easy to control information flow.

Type: I recommend jump troops since they would work better for your Stealth insertions. Additionally, The Standardized equipment will not draw attention to your Secret project.

Here's a homeworld i came up with:

Claimed by the Rosette:

it is not uncommon for men and women of the Imperium to find themselves of use to an agent of the Holy ordos of the Inquisition. many a man or woman has been taken from their home by an Inquisitor or his agents for the skill that individual has. although many a soul blanches at the idea of being stripped of their former lives to serve the inquisition, many blighted souls, such as prisoners, failed students, and soldiers before a firing squad, jump at the chance to cast off their former ties to join the inquisition.

Attributes: +3 to any one attribute, and Unnatural Strength (2) Unnatural toughness (2) or Unnatural Willpower (2)

Skills: Forbidden Lore (Inquisition), and Stealth.

Agent of the Holy Ordos: Regiments under the permenant command of an Inquisitor are rare, and highly frowned upon, but they do exist. Soldiers in Such regiments often recieve priority for equipment meant for other units, and can even Request equipment not meant for the Imperial Guard at all. Regiments from this homeworld treat all equipment as one level more common for the purposes of Logistics tests. However, any time the Squad Rolls a 01 or any doubles, they draw the attention of not only the Munitorum, but of another Inquisitor who wants to know why supplies are being sent to a warfront where no identified imperial forces are deployed...
Something's not right with them: No matter how hard they hide it, Soldiers seconded to an Inquisitor are marked by their experiences in ways that puts others ill at ease. whether it's a set of scars that clearly were made by something not of this reality, a curious ability to dissect a person's personality and motives after only a few exchanged words, or a simple, palpable aura of wrongness, other Guardsmen and Naval Personnel see them as bad news. Soldiers from this homeworld take a -30 penalty on all interaction tests with Guardsmen and Naval Personnel not of their regiment.

Of many Origins: Guardsmen of an Inquisitorial Regiment come from many different backgrounds, and thus have many different defining qualities. Guardsmen from this homeworld may take one Talent offered by any other Homeworld Option.

Wounds: Soldiers of this Regiment start with +1 Wounds

Cost: 6

Thoughts?

Yes drop the Unnatural Willpower unless you disallow Psykers completely, and raise the point cost to 6.

This is definitely an interesting concept. I might have to crib this for something I'm looking at doing in my game. Oh, you also might want to peek at the gland warriors for RT Into the Storm, they seem like they're being hyped as low tier space marines. The idea that you have though is pretty cool.

I'd also agree to dropping unnatural willpower, in this case I'd say just do it period.

Since it's "Unnatural Toughness (2) or Unnatural Willpower (2)", I would say that you should allow it, but due to the nature of the regiment, it makes no sense to have many of the Specializations either way, such as the Stormtrooper, Abhumans, or Psyker. Just disallow the regiment from taking those and it not only works out better thematically, but also allows you to maintain the possibility of characters choosing Unnatural Willpower.

I'd also drop the Hated & Feared; the effect of the Inquisitorial Rosette and Agents of the Throne is invariably the opposite, unless you are dealing with complete heretics. But more importantly, I think it makes no sense that, as a covert inquisitorial regiment, they'd be in any way identified on their persons as operatives of the Inquisition. Squad or Platoon leaders might have command codes or a writ from the Inquisitor in the event that they need to identify themselves to other imperial organizations, but apart from that.. no.

If the purpose is to create a penalty as to try to keep the characters apart from other regiments and guardsmen, I would recommend keeping the same penalty, but expand it to also include Navy personnel, and attribute it to the obvious "otherness" within the military that these soldiers would exude, due to their many strange enhancements, biological quirks, and so on.

Also, I'd straight-out rip the Gland Warrior Talent from Rogue Trader: Into the Storm and use that as a basis for fluffing out the way these soldiers have been "enhanced".

Homeworld's been edited, kept Unnatural Willpower, but I will be axing Psyker's as an option.

Right, here's what i've got Mechanically. i'll put up an actual official writeup later tonight, but for now, the rules crunch:

Blackwatch:

Characteristic Modifiers: +2 Weapon Skill, +3 Agility, +3 one Attribute of choice, Unnatural Strength (2) Unnatural Toughness (2) or unnatural Willpower (2)

Skills: Operate (aeronautica), Forbidden Lore (Inquisition), Stealth

Talents: Catfall, Street Fighting, one talent of player's choice from any homeworld option.

Agents of the Inquisition

Something's not right with them

of many Origins (factored above in Talents)

The Few (HoE)

Wounds: +1

Starting Gear: Standard Guardsman Kit, one M36 Lasgun with Six Charge Packs per guardsman, one Laspistol with four charge packs per guardsman, one chainsword per guardsman, one suit of Light Carapace Armour Per Guardsman, one Respirator Per guardsman, one Grav chute per Guardsman, one mono-knife per guardsman

Favored weapons:

Meltagun

Autocannon

Restricted Classes (not outright banned, but the player has to have a REALLY compelling reason to get it his way): Storm Trooper, Psyker, Comissar

Banned Classes: Ogryn, Ratling

If you include the Psyker you should exclude the Unnatural Toughness.
Psykers in OW have a tendency to kill everything, with WPB +2 this would be insane...