In response to Lechlerfan and the question in his bounty; here are my thought's on the topic, as looking in the DMG 1&2 and the RC do not address this particular scenario (as far as I can find in the sections concerning XP rewards or NPC allies). The books actually don't mention NPC allies that I can find, other than during NPC creation where it says you may want to make NPC allies as fully fledged characters.
First: Why do we divide XP at all?
Dividing the total sum of XP per encounter by the number of players is to keep the players progressing at the same pace and to reward them equally for working together to accomplish a challenge. (Each character likely contributes in their own unique way and this rewards their individual contributions.) In my opinion it also keeps PC's from leveling too quickly, they do need experiences to gain XP and improve skills (the term "experiences" here obviously refers to the actual sights, sounds and interactions they have).
Second: What do I do about NPC allies?
Some options to consider:
- Temporary NPC Ally:
- Temporary NPC allies should not receive the XP if they are not going to be around long enough to Level up. Though still divide the total XP amount as the PC should only be rewarded for their contributions.
- Do allocate the NPC XP if they will be around long enough to level even once.
- Permanant NPC Ally:
- Definitely award XP to a permanent NPC. You want to level them along with the PC so they stay roughly as powerful as the PC. (Suggestion: You could have them be a level lower or so to make the PC feel more important/powerful.)
If you feel the need to reward the player more than the NPC (and why wouldn't you?), perhaps counting them twice during the XP split would be an option. So, 1 PC and 2NPC just completed an 800xp fight, if you divide equally each of the 3 characters receive 266XP. However, if you count the PC twice and divide by 4 the PC gets 400xp while the NPC's get 200 each.
Third: How do I build the encounters?
Here are 2 options for building the encounters.
- Build the Encounter to be accomplished by 1 player.
- At this point you know the encounter should be able to be completed by 1 player and therefore you can disregard the NPCs and just give all the XP to the player. (Sub-par option in my book as it makes things too easy if the player has help)
- Build the Encounter with NPCs in mind.
- This is what I would do in Lechlerfan's situation. Assume that the NPC's will be hanging around for a little while, treat them as "players" and create the encounters to challenge a player group the size of the party, NPCs included. Then dole out XP as you would for a group if the NPC Allies were actually players.
To summarize exactly what I would do from these options, I would assume the NPCs are part of the party and create encounters to challenge the party as a whole. Then to make sure the Player(s) level at the game's recommended speed, I would give out XP as if the NPC's were players (Divide total XP by number of party members). I would then only keep track of NPC XP if they are intended to level with the PC throughout the game.
To remark on your worry about it feeling like you are penalizing the player for using NPCs do to a perceived "loss" of XP, explain to the player why you divide XP. Explain that if there were actual players there you would be dividing the XP the same way and that his character is getting his fair share of the reward for his contributions to the challenges. If he decides to go about it alone for a while he will either succeed and be rewarded for accomplishing a harder task, be forced to retreat, or die. The latter scenarios may show the player that having allies is good and worth the "lower" (though not really) XP per encounter.
Again, there is nothing in the rules I can find that discusses XP allotment to NPC allies and these are just suggestions to a unique problem.
PS: I was under the impression you wanted to dole out XP the "traditional" way, i.e. adding up standard XP per monster/trap/skill challenge and then dividing among the player participants.
There is a second option however... Don't give out "XP" at all. Just follow the rule of thumb that PC's are supposed to level after 8-10 encounters. This way you skirt the entire issue of "Where did all my XP go?" and your player levels up at the game's recommended pace regardless if (s)he utilizes NPCs.
From DMG1 page 121 (emphasis mine):
Tell the players that they gain a level after they complete 8 to 10 encounters. Don't count really easy encounters, count really hard encounters as two, and don't worry about precise XP totals.
One note about this is that the rules encourage you to treat completing a quest (presumably the action of returning to the challenge issuer victorious) as worth the XP of a normal encounter. So, in the above example would be 6-8 encounters with 1-2 quest completions.
Sorry for such a lengthy answer, but I wanted to cover all the options I could think of (plus since this isn't in the Rules I basically just wrote a section of the rules book ;) ).