So a PC in my Runelords game is becoming a Hellknight.
I've got a really fun scenario I'm adapting from here on the boards (courtesy of James B. Cline), though in that he has the PC fighting a Dretch Demon, not a devil. I wanted to swap it out w/ a Devil, but I've never run a solo scenario, and I don't want to kill my PC (or make it a cakewalk).
So, do you think it more appropriate to use a CR3 Zebub Devil against a lvl 4 Two Handed specialist armored fighter (played by an experienced gamer)? Or should I push and go with a Bearded Devil (CR5)?
I had heard that a solo encounter should be APL-3, so that really puts him as a lvl 1 party. Given that, a CR3 would be a difficult but winnable battle.
My hesitancy is that one crit from him could almost drop the Zebub (30 HP). He's got Overhand Chop, power attack, and weapon focus, so his normal bonus dmg is +12 when he hits. Plus, the Zebub's AC is 17, so I'm thinking he'll only last 2-3 rounds. The environment won't allow the demon's flight to help it that much, so the best tactic I could think of would be use grease to limit his movement while invisible, then get it position, attack, and fly away (giving one AoO). However, after the first time, he's going to just ready to attack when he appears, so again, 1-2 rounds and he should be dropped.
But when I look at the Bearded Devil, the AC/HP seemed more like a challenge, but I didn't know if the damage it deals could too easily drop the PC. From the CR guidance above, I'm not sure I'd want to give a CR5 to a group of lvl 1 PCs... so I'm torn.
Thoughts?
CR isn't the best way to determine exactly how to build encounters. It's a nice basis, but there's to much variability to use them exclusively. I'd run with what you feel with fit with your players more than what the book says is appropriate. If you're dealing with an experienced player, he can usually handle more than what the book suggests, since the books are general written with average characters in mind rather than more efficient high-power characters that most experienced players are easily capable of building.
If I was in your place, I'd use the bearded devil, but it's a very challenging fight so you'll need to be careful. He can stand up more in an outright fight instead of having to rely on tricks to take potshots, but he's going to deal out a lot of damage. There's nothing wrong the zebub fighting like that, but it's rather frustrating for a martial character to have to try and fight that kind of enemy solo.
The Zebub gets an average of 7 damage a round, which probably won't make the fighter even blink for a few rounds, and unless he gets an ambush off on the fighter, he's taking an average of around 19 damage (depending on weapon) on his first round. That means it only takes 2 rounds to put him down. He'll be dead before he even has time to set up the battlefield unless the fighter is essentially walking into a massive trap. Of course, setting it up to be a massive trap would be amusing, but I have a feeling that's not what you're going for.
The Bearded Devil gets an average of about 22-32 damage (depending on if he Power Attacks) a round, which is a lot, but only if he gets both hits. His second attack is more likely to miss, so it's a little better. One hit deals on average 11-17 damage, which isn't unbearable for a good martial character. If he has healing items, he'll be able to handle more too, but I have no idea how he's equipped. The fighter can still take him in 3-4 rounds (depending on how often he hits) but he'll have to be more careful due to having an enemy that could possibly kill him with some good hits.
Either works based on set-up, but that's my two cents.