newbie question on DC

I am looking at possibly starting a rogue or mage, or whatever campaign with a friend of mine, and so I'm wondering, in what way do I need to modify or look at DCs differently so that my solo friend can survive encounters? iirc a dc 1 is for a party of 4 level 1 characters, so do I need to divide everything by 4 and say he should start with DC 1/4 encounters?

Thanks in advance for advice

I think you're looking for the term CR (Challenge Rating) or EL (Encounter Level). The staock answer is that you should reduce ELs by 4 points, so if you'd normally use a CR 10 against a group of his level, you should use a CR 6 against him alone. Unless there are special features, you should send him against CRs 4 lower than his level when he's encountering a few in a day.

If he's level 1, use CR 1/4 for such encounters; level 2, CR 1/2; levels 3-4, CR 1, level 5-6 CR 2.

I assume you mean CR?

There's really no easy way to answer this, beacuse a)You don't mention what stats this character will have, making it hard to judge power level, and b)CR is a very rough quideline. CR/4 might be ok at level 1 or 2, but things would quickly get too easy... "Appropriate" CR - 4 sounds about right, but keep in mind that a critter using poison or a grappler going after a mage, or an undead monster facing a rogue will be a lot tougher for them than CR will indicate - they're meant to be fought by a whole party.

Still, here are a couple of the things you should keep in mind if you intend for this character to survive:

1. Look for monsters and enemies that can put up a fight (decent AC, decent HP) but don't dish out a lot of damage.

2. Be very careful when using magic against the character - a single "Save or Die" spell (Sleep, Hold Person, or anything else that stuns or disables for several rounds, in this case) can end the character's career instantly, because there won't be anyone around to cast Dispel Magic at him or protect him until he comes to. So unless you want him to get "resurrected by mysterious stranger" or "captured by enemies only to escape again" you might want to be careful with that.

3. Provide him with some sort of renewable healing item (family heirloom, gift from his master, whatever) - he'll need it.

Ignore CR if there's just one PC.
You'll have to compare each opponent against his abilities by hand.

One PC makes things a lot more difficult, assuming that you want the to have challenging-but-not-deadly fights, as a group can bandage up the guy who gets KOed, dispel nasty spells, or hold off the baddies while the guy who got clobbered recovers.

With one PC, one bad roll can wipe out the entire campaign.

Geoff.

You might want to consider either running an NPC companion, or letting the player play two characters at once (or combine the two -- have an NPC that the player runs in combat, but you get "veto" authority and generally run out of combat). It would make things a lot more survivable (especially if both characters can use wands of cure light wounds).

For a two person group, you'd reduce ELs by 2 to get vaguely appropriate challenges. You'll still need to be very careful, of course.