So, I've been GM for my small group for a while now, and we'll soon have an extra player giving it a go at least once. However, the 4 existing characters are all about 6000xp, so we're pretty far in to our story, and the new guy has no rpg experience. As the next stage of the story takes us into a near completely automated ship (25 non-servitor crew) stranded for several hours and with a daemon prowling throughout, I thought I would make new guy one of the armsmen, naming him Rufus Indusium for the night. This lets him jump in quickly and means if he is messily slaughtered a 6k xp character sheet doesn't have to be drawn up twice. My concern is whether 6k is too high a level for a complete newbie, even with the support of a fairly well experienced party.

It depends on how you look at it, really. Me, personally, would have a very hard time explaining why one of the simple armsmen would be a special person with a special destiny, hauling around 6000xp yet stuck in a dead-end job on the road to nowhere.

But that's fluff and that's different strokes.

However, in general, there's not that much separating a 0xp and a 6000xp character when it comes to sheer survivability, apart from possible +wounds advances, Agility and Toughness, which at most is +/-20. The biggest difference is going to be in what abilities he have beyond that, in Skills, Talents and killyness.

My go-to principle is that latecomers (character-wise, not player-wise) get half the experience of pre-existing characters, in this case 3000xp, with possible bonus xp during play due to good roleplaying and "added life experience" from hanging out with the more experienced people and experiencing what to them (the other characters) are now possibly routine ("Oh, another daemon? Pass the melta bombs.").

Handle them in the same way as a player who had been absent for all the preceeding sessions and give them half xp.

Taking up a scrub to 3k is bad enough believe me. Also avoid giving talents that cut corners like quickdraw off the bat so your newbie can learn the mechanics.

I don't think this is a game that works well by not keeping everyone at the same relative XP level. There are huge competency and talent gaps at 3000 vs 6000 XP in this game compared to a more narrative game.

And if he's messily killed, he has Fate to burn to prevent dying, big deal.

The system I use for integrating new players into an existing group was suggested by D&D3E : put them at the mid-point of the level below the lowest level member of the existing group. That way they are still 'viable' power-wise but not able to 'eclipse' the veteran characters who were there from Day 1. Its not a perfect system, but it works.

With regard to the new character, even starting a bit lower Rank than the current PCs would be hard to justify for a mere armsman; I'd make him Security Chief, backed up with a military background.

Everyone has given helpful ideas so far, but let me clarify - the armsman I give the newbie to play isn't intended to be his permanent character. There are a handful of armsmen on the ships skeleton crew, and newbie will be given anonymous armsman #4 to control for the night, to get a feel of the rules, setting, and group. Rufus Indusium, the name hes getting for the session, literally translates to red shirt. If he dies, he can jump into the next surviving armsman, this is why I won't need to roll up a new character if his inexperience gets him turned into interior decorating. If he wants to make a permanent character after this session it would be rolled up and collected next planetfall. XP levels come into consideration at that point.

Make him at the same level as the players; since he's a one shot character, might as well get the most toys and talents he can get; I suppose armsman would be a Guardsman? 6K it is, at least he would be able to do some damage in combat rather than being the red shirt assistant.

I got 2 new players when the current mission started, I made them at rank 8 as my normal players were; no point in starting so low on the totem pole that you're almost useless.

Everyone has given helpful ideas so far, but let me clarify - the armsman I give the newbie to play isn't intended to be his permanent character. There are a handful of armsmen on the ships skeleton crew, and newbie will be given anonymous armsman #4 to control for the night, to get a feel of the rules, setting, and group. Rufus Indusium, the name hes getting for the session, literally translates to red shirt. If he dies, he can jump into the next surviving armsman, this is why I won't need to roll up a new character if his inexperience gets him turned into interior decorating. If he wants to make a permanent character after this session it would be rolled up and collected next planetfall. XP levels come into consideration at that point.

If it's just a one-off character, I would just give him a pre-made character tailored for high survivability and without the many "amenity"-Talents, and as a diverse skill-set as possible.

Then play the session as an introduction adventure to him, with some specific "checkpoints", such as Lore Checks, Skill Checks, and an advanced (as in, intricate and full of options, cover, etc; not hard ) combat scenario.

And then I'd let him create a character with ~3000xp, setting him up to scale slightly faster than the rest until they are at approximately the same "power level".

Oh, for a one-off a 3k experience sounds good if only to get used to the system. I would agree though that it'd make more sense for him to be a senior armsman, senior NCO, etc on the ship instead of some random grunt.

After that I'd set him to the default XP of the rest of the party and include part of his backstory as being part of another cell for the same Inquisitor or one of his/her close colleagues. I really don't like that half-power method because it seems punitive to the new person, nor do I like half power plus accelerated XP gain for them (too much different bookkeeping).

You should almost always start a new player at exactly the same exp as everyone else, and your group for helping the new player should almost always have fully the same exp between each player.

Separate leveling is something pretty much only experienced groups handle well.

As he's a new player, you should probably run through basic character creation with him, leave 6000 exp available (technically awarded), then just go through the basics of getting him in the game at roughly the same power as the others.

Then perhaps allow him to switch out or buy things with the exp as he gets more experienced.

Fluff is a non-issue because there are tons of reasons a ship might have a highly skilled operative on board, from him being a stranded plant from another inquisitor, to a highly skilled guardsman who got exiled on punitive duty.

Power gaps between PC competency can leave a sour impression in a new player. It's a bad idea to punish people for either not being able to attend a game session or for arriving late in the campaign. I keep all my players at the same XP level regardless of who shows. Granted, DH handles mixed XP totals better than other games, but it's still a bad idea.

For your specific situation, if I were you I'd write up a 6k character sheet with a focus on combat abilities since those are the easiest to see the direct effects of. He may want to continue playing Rufus if he likes the character. If he does, let him re-spend some of the XP if he doesn't find what you chose useful (so keep a list of what you buy and for how much).