The two most basic choices you have when making a character are “where do they come from?” and “what do they do?” The Imperium is a truly vast place, and any attempt to catalogue all the worlds within it is doomed to failure. It is also equally varied, some planets being not unlike our own, while one may have it’s cities built on rocky outcrops perched above the clouds, and another may be nothing but vast fields of crops with it’ entire industry dedicated to producing food for nearby planets. In game terms, though, your possible origins are broken down into four groups.
Feral Worlds: Primitive and harsh worlds, the natives of such places are well adapted to the hard lives they lead. Such people tend to be superstitious and unfamiliar with technology, but they make up for it in self sufficiency and physical prowess. Further information is on pages
14 and
15.
Hive Worlds: Hive worlds are usually barren wastelands, the natural environment decimated by centuries of heavy industry. The vast populations live in vast hive cities, some spread out across entire continents, others reaching up kilometers into the sky. The toxic conditions (or the high living of the noble classes) leaves hivers less resilient than most, but far more used to dealing with their fellow man from the constant hustle and bustle of hive life. More info can be found on pages
16 and
17.
Imperial Worlds: This category covers the largest variety of worlds. This category includes agri-worlds, low-key backwater worlds, worlds dedicated to the Ecclesiarchy and the worship of the Emperor or a paradise world for the elite of the sector. It also includes even odder planets, such as vast ice-worlds where the population lives in subterranean cities or vast fortress worlds where military service is the norm and the threat of invasion looms constantly. Imperial worlders are, compared to the stranger varieties of humans, pretty average. More information can be found on pages
18 and
19.
Void Born: You are a strange sight to the rest of mankind. Born aboard a space faring vessel, orbital installation or perhaps even a ship undergoing warp travel, you are touched by something and find it hard to relate those who weren’t born aboard. You may find the universe outside of your ship as strange as a feral worlder does, but you are more at ease with the strangeness and oddities having grown up around the psykers necessary for warp travel. More information can be found on pages
20,
21 and
here.
Your homeworld will colour how your character thinks and behaves. If you need inspiration or want to pick an example, look at pages
32 and
33. Guides and randomization charts for your appearance can also be found later on in chapter 2.
Once you’ve chosen your home world your next step is to choose your class. Each class is split into 8 ranks or "careers," each giving some definition to your potential abilities. The later ranks of each class can split down different paths, each focusing on an aspect of your class. There are 8 classes in total, though only those from Imperial worlds have the luxury of becoming any. See the home world pages relevant to you to see what classes you can be.
Adept: Adepts are the masters of knowledge, this class encompassing the myriad of scribes and bureaucrats pepper the Imperium, along with anyone who puts serious effort into study. They may not be as skilled in a fight as one of the more martial careers, but they will almost certainly know more about most things than anyone else. They make fine investigators, researchers and are fairly good at dealing with people, too. For more information, see page 44.
Arbitrator: More than mere planetary police, the Adeptus Arbites preserve Imperial law and investigate matters concerning the greater needs of the Imperium. As such they are the most likely of all careers to encounter an Inquisitor or his servants during their duties. Arbitrators are part investigators, part riot police. That’s what the shotgun is for, after all. More than anything, though, they are smart, tough and determined. For more information, see page 50.
Assassin: An assassin comes in a myriad of forms, from the skulking blade-for-hire to the high-society poisoner to the demented death-cult assassin. All assassins are good at one thing, though: dealing death. A soldier can take a slug to the chest and keep on fighting, but in terms of raw killing power the assassin excels. He is skilled and quick, though he has little use for brute force or the camaraderie of others. For more information, see page 56.
Cleric: Whether a respected member of the Adeptus Ministorum or a more informal missionary, clerics are charismatic men of faith. No other career can demand such attention from the masses, nor inspire them to such feats of bravery and zeal. The cleric is no slouch in combat either, though his prowess often relies more on fanaticism than training. Clerics bring the light of the God-Emperor to both the faithful and to the heretical. In the latter case this is most usually on the business end of a flame-thrower or a chainsword. For more information, see page 62.
Guardsman: The guardsman is a man of action, pure and simple. This career encompasses more than those recruited from the vast armies of the Imperial Guard, covering local planetary defense troops, mercenaries and tribal hunters from feral worlds. They are strong, though and able. When the shooting starts you can rely on a Guardsman to win the day. For more information, see page 68.
Imperial Psyker: Imagine wielding incredible power; the ability to mend flesh, hurls bolts of telekinetic energy or cast your vision vast distances. Now imagine that the price of this is a door. Should you ever turn your attention away from this door, even for a moment, hordes of demons will spill through and bring ruin on what they find. Now imagine this door is inside your head. The Imperial Psyker is both blessed with incredible abilities and cursed in that he takes a great risk each time he uses them. The terrors of the Immaterium, or the Warp as it is better know, are drawn to then like bees to honey, for it is through them that they might enter the material realm. Even though they have been tested and sanctioned by the Black Ships of the Inquisition these individuals are regarded with fear, mistrust and often outright hatred by the common man. The Imperial Psyker is weak in body but strong in mind and, if he manages to survive against the odds and develop his power, a truly terrifying foe. For more information, see page 74.
Scum: This career covers perhaps the widest range of people, from back-alley muggers to dashing rogues to underhive gangers. They all share one thing, though: they are outsiders to Imperial society in general and make their own way in the world, and often have questionable opinions on topics such as morality and legality. Scum are alert and quick thinkers, quicker on their feet, and even more so with their tongues. They don’t excel in a fight, but they know how to handle themselves. For more information, see page 82.
Tech-Priest: The 41st Millennium is not an enlightened age. Technology is a strange and arcane thing, and only those versed in the correct rituals and observances know how to attend to it. A soldier may be able to strip and perform maintenance on his las-rifle, but he will have little, if any, idea of how it works. He just knows to rub the sacred oil here while reciting the appropriate litany. The Tech-Priest of the Adeptus Mechanicus are a society unto themselves, even having their own concept of the Imperial Creed. They revere the Omnissiah, popularly believed to be an incarnation of the Divine Emperor, who is the source of all technology. Technology itself, of course, represents a higher form of evolution than mere biological life. As they rise within the ranks and learn more of the secrets of technology a tech-priest replaces more and more of his weak and feeble body with the True-Flesh of machinery. Their proficiency with machines utterly dwarfs that of any other career and their augmentations leave them highly resistant to damage. Notably, though, they care little the illogical, such as emotion, instinct and most other humans. For more information, see page 88.
Next up we’ve got your characteristics. If you look at the character sheet you’ll see you have 9 of these, which are also listed below.
Weapon Skill: Your aptitude with melee attacks.
Ballistic Skill: Your aptitude with ranged attacks.
Strength: You physical strength.
Toughness - How easily your shrug of injuries, resist toxins, poisonous environments, diseases and other physical ailments.
Agility: Your quickness, reflexes and poise.
Intelligence: A measure of your acumen, reason and knowledge.
Perception: How well you perceive your surroundings and how acute your senses are.
Willpower: Your ability to withstand the horrors of war, the terrors of space and the awfulness you are bound to encounter in your missions.
Fellowship: Your ability to interact with others and how well you can deceive, charm or befriend them.
You will have a base score of 20 in most of your characteristics, though this varies depending on your world of origin (see page 23 for the base scores of each character). For this RP you’ll get to roll 10 sets of 2d10 (each yielding a result of 2-20), pick the best 9 and assign them to whatever characteristics you want. For example, let’s say you roll 8, 20, 14, 7, 11, 9, 6, 9, 6 and 4. You discard the 4 and apply the rest to your characteristics. If you were playing an Adept from an Imperial world (20 as base for all) you may end up with these characteristics.

You also have a derivate stat for every characteristic except for WS and BS; your bonuses. These are the first digit of your characteristic score. Using the above example, we would have a Strength bonus of 2, but an Intelligence bonus of 4. Note these down in the areas to the right of each characteristic on the character sheet. Now would also be a good time to fill in the information and effects of your homeworld traits. Our adept here is from an Imperial world and, as such, counts a number of skills as basic rather than advanced (he can attempt to use them untrained), takes a penalty to all Forbidden Lore tests and gains a +3 bonus to his Willpower.
The next step is to consult your starting skills, talents and gear on pages 24 to 27. There will be some choices to make here. For example, the Guardsman has to choose between taking the talent Pistol Training (Solid Projectile) OR taking the talent Pistol Training (Las). If you chose to be a Tech-Priest you will also receive all the augmentations listed on page 27. If you chose to play an Imperial Psyker then you must roll a d100 and consult the Sanctioning Side Effects table. The processes used to determine whether a psyker is strong enough to resist the perils of the warp are many, varied and largely unpleasant. You also get to choose a number of Minor Psychic Powers equal to ½ you willpower bonus (rounding up). Select these from the list on page 165.
Next, on page 28, you take care of miscellanea such as wounds (how much damage you can take before suffering critical injuries), fate points (a measure of destiny, divine purpose and plain luck) and movement. You also determine your starting funds based on your career. You also have 400 experience points to spend, as do all starting characters. This represents your experiences before being recruited to serve the Inquisition. You can use these to buy characteristic advances or skill and talent advances from the starting rank of your career (see the previously linked class pages). Make sure to update the bonuses of any characteristic and remember to note down your advances both on the main body of the character sheet and the “Advancements Taken” section at the bottom of the left hand page.
The last thing that needs to be rolled for is on page 34: your Divination. Roll a d100, consult the table and note down the effects on your character sheet. Your character’s appearance is up to you, as is their background, though I recommend you read page 35 before finalizing the latter. Pages 30-31 will provide an idea of what your character might look like, and pages 36-37 can help you decide on a name if you’re really stumped.
An example of a finished character can be seen
here.