-On The Binding Of Fiends-
Ok, so now that we are a Fiendbinder we can get busy with the binding. First we have to research the truenames of the fiends we bind. There are a couple ways to go about doing this. If you have a liberal DM we can just Planar Binding our target and force it to tell us it's truename. You'll want to tip the scales in your favor with debuffs if you go this route. Here is a list I am blatantly stealing from
Treatmonk's Guide to Mastering The Malconvoker.
Enchantment:
2nd: Touch of idiocy (PHB): 1d6 loss to CHA
2nd: Rebuke (SC): Shaken subject (-2 Ability checks)
2rd: Mechanus Mind (SC): Gives a bunch of bonuses, but -2 to CHA checks
3rd: Suggestion (PHB): Possibly just suggest the creature agree to your terms
4th: Charm Monster (PHB): Make the creature want to be your ally
4th: Crushing Despair (PHB): -2 to ability checks
4th: Geas, Lesser (PHB): 1 day/level up to 7HD - force them to accept your terms
Transmutation:Necromancy:
1st: Cause Fear: (As Rebuke)
2nd: Scare: (as cause fear or Rebuke)
2nd: Ray of Sickness: Cause sickened effect (-2 to ability checks)
4th: Bestow Curse: Use 2x. Lower CHA by 6, then lower ability checks by 4
4th: Enervation: Negative levels (-1 to ability checks per level lost)
With the proper application of debuffs the target should cough up it's truename rather easily. If your DM just threw a book at you, then you'll have to do it the other way. Pump your Knowledge (The Planes) up, and research them names! Then go to a library. It'll cost you 500gp (twice that without the library) and a week of time per 2/hd of the fiend you want to bind. If you fail the check you've wasted some money, so use spells and items to help you out there.
Another possibility is asking the Planar Binding'ed Fiend to help you inconvenience a rival. Bind up a succubus and ask her if she knows the truenames to any succubi who she'd like to embarrass or get out of the way for a while. Some Diplomacy and/or Bluff rolls might be appropriate here.
Now that we have the name we need, and we get down to binding our fiend. This is a simple process, you just pay a set amount of gold. You dont even need to make a roll, its just automatically successful.
-The Fiends Themselves-
At each level the fiendbinder gains a new type of fiend to bind. It's important to note that even though the table lists the standard demons and devils, there is nothing that says we can't bind an advanced version of the same fiend. Doing so just means you'll have to deal with a harder truespeak check. This is something you'll want to discuss with the DM, since the fiends will become less and less useful to more you level, but if you can advance them, well, they can retain allot of their potency.
Babau Demon: This is the first fiend that you can bind. For 2,700 GP you can get a slimy little demon to eat your foes. He has 7 Hit Dice, two claw attacks and a bite. He also sneak attacks at 2d6. He is nice and sneaky, with open lock and disable device, and a hide and move silently of 19. Another bonus is the at will darkness, and
dispel magic. Note that if you want to play with a babau and you aren't a fiendbinder you have to wait till 13th level (14 for sorcerers), and cast Summon Monster VII. For 4,200 GP (with the research cost) you are getting a permanent 7th level summon hanging around, five levels early. Not too shabby.
Succubus: Your second level bind, she costs 3,600 GP. She has a nice Energy Drain ability which can come in handy, change shape ability so she can look like anybody you want (and fulfill your most dastardly desires! Feel free to have her walk around as a sexy asian chick if you like), tongues, telepathy, flight and her spell likes. At will charm monster, detect thoughts, and suggestion.
Hellcat Devil: This is sort of a
meh bind. Invisibility in well lit areas is nice, but it doesn't have any spell likes to use. It does have pounce and rake, and it attacks at +13 so its a decent scout/melee. It can grapple with improved grab too. Overall though, I'd rather more spell likes.
Vrock Demon: Oooh happy dance. For 6,600 GP you can get this baby which has Flight and Claw/Claw/Bite/Talon/Talon. Also spores is a nice damage over time effect it can do as a free action. Spell likes are Mirror Image and
Telekinesis at will, and 1/day heroism. Dance of Ruin is nice if you can bind 3 of them. Stunning Screech is also nice, a 1/hour 30 foot burst stun. Remember to stay out of the range of Stunning Screech and Dance of Ruin.
Cauchemar Nightmare: Holy Flying Mount Batman! +23 to Hit with its Hooves (2d6+10 +1d4 Fire), and a bite attack, 90ft. Fly speed and then we get down to the really good parts: Astral Projection and Etherealness at will. Yes, two ninth level spells at will... at 13th level. This baby costs you 8,800 GP, and is a decent excuse to pick up some ranks in Ride.
Retriever Demon: Things just keep getting better and better! A huge construct, 4 claws and a bite, and a free eye ray each round (12d6 Cold, Fire or Electricity, and the last does Petrification!), can find anything you've seen with perfect accuracy. Improved Grab is just gravy. At 11,000 GP, this is a better option than any other 10HD ish construct.
Hezrou Demon: This is sort of lackluster at this point. Chaos Hammer and Unholy Blight at will, the stench ability can be both boon and a hinderance. Improved Grab too. A strait up bruiser but not a terribly powerful one. It does have Gaseous Form 1/day and blasphemy 3/day. Too bad it's caster level is only 13, good for disabling annoying things. You can snag this guy for 15,000 GP.
Barbed Devil: Fear effect on hit, hold person, major image and scorching way at will. Overall it is sort of meh. You can get this guy for 20,000 GP.
Ice Devil: Wow. This guy makes up for the Hezrou and the Barbed Devil. A High AC, Regeneration, Fear Aura, Slow effect on the spear or tail, and the Spell likes! Wow, the spell likes are so awesome. Cone of Cold, Fly, Ice Storm,
persistent image, Unholy Aura, Wall of Ice, all at will! At 26,000 GP this guy is a STEAL!
Marilith Demon: This is the capstone. Forget about the actual capstone, because this is really it. Six hands! A Massive attack routine, improved grab, constrict, and True Seeing. The Spell likes are Align Weapon, Blade Barrier, Magic Weapon (Yay!), Project Image, See Invisibilty and Telekinesis. An Excellent use of 34,000 GP.
-Advancing Your Fiends-
There are Several ways to improve your fiends, lets discuss those now.
Increasing Hit Dice: The truespeak DC is actually based on 15 + (2xCR), and using this formulae we can figure out how to command more advanced fiends. That babau demon might start looking rather poor by the time you get a few more levels. For each 2 HD you add to a fiend you increase its CR by 1. Each CR bumps the check by 2, so on a 1 for 1 we can improve our fiends. This way we can select their feats and distribute their skill points as we need.
Equipment: Your fiends stick around, this is amazingly beneficial because now we can equip them. Giving your fiends armor and weapons will greatly increase their damage potential. Try giving your succubus a cloak of charisma, for example.
Buffs: Any buff that your fighter would like, your fiend is likely to like just as much. This makes group buffs even better. If you have a cleric in the group you should convince him to go the reach spell + chain spell buff route.