One thing to consider;
PIT FIEND, 4E VERSION
Pit Fiend Level 26 Elite Soldier (Leader)
Large immortal humanoid (devil) XP 18,000
Initiative +22 Senses Perception +23; darkvision
Aura of Fear (Fear) aura 5; enemies in the aura take a –2 penalty on attack rolls.
Aura of Fire (Fire) aura 5; enemies that enter or start their turns in the aura take 15 fire damage.
HP 350; Bloodied 175
AC 44; Fortitude 42, Reflex 38, Will 40
Resist 30 fire, 15 poison
Saving Throws +2
Speed 12, fly 12 (clumsy), teleport 10
Action Points 1
Melee Flametouched Mace (standard; at-will) • Fire, Weapon
Reach 2; +31 vs. AC; 1d12+11 fire damage plus ongoing 5 fire damage (save ends).
Melee Tail Sting (standard; at-will) • Poison
+31 vs. AC; 1d6+11 damage, and the pit fiend may make a free followup attack. Followup: +29 vs. Fortitude; ongoing 15 poison damage, and the target is weakened (save ends both effects).
Melee Pit Fiend Frenzy (standard; at-will)
The pit fiend makes a flametouched mace attack and a tail sting attack.
Ranged Point of Terror (minor; at-will) • Fear
Range 5; +30 vs. Will; the target takes a –5 penalty to all defenses until the end of the pit fiend's next turn.
Ranged Irresistible Command (minor 1/round; at-will) • Charm, Fire
Range 10; affects one allied devil of lower level than the pit fiend; the target immediately slides up to 5 squares and explodes, dealing 2d10+5 fire damage to all creatures in a close burst 2. The exploding devil is destroyed.
Infernal Summons (standard; encounter) • Conjuration
The pit fiend summons a group of devil allies. Summoned devils roll initiative to determine when they act in the initiative order and gain a +4 bonus to attack rolls as long as the pit fiend is alive. They remain until they are killed, dismissed by the pit fiend (free action), or the encounter ends. PCs do not earn experience points for killing these summoned creatures. The pit fiend chooses to summon one of the following groups of devils:
8 legion devil legionnaires (level 21), or
2 war devils (level 22), or
1 war devil (level 22) and 4 legion devil legionnaires (level 21)
Tactical Teleport (standard; recharge 4 5 6) • Teleportation
The pit fiend can teleport up to 2 allies within 10 squares of it. The targets appear in any other unoccupied squares within 10 squares of the pit fiend.
Alignment Evil
Languages Supernal
Skills Bluff +27, Intimidate +27, Religion +24
Str 32 (+24) Dex 24 (+20) Wis 20 (+18)
Con 27 (+21) Int 22 (+19) Cha 28 (+22)
Equipment flametouched mace, noble signet ring
contrast with...
PIT FIEND, 3.5 VERSION
Size/Type: Large Outsider (Evil, Extraplanar, Lawful)
Hit Dice: 18d8+144 (225 hp)
Initiative: +12
Speed: 40 ft. (8 squares), fly 60 ft. (average)
Armor Class: 40 (-1 size, +8 Dex, +23 natural), touch 17, flat-footed 32
Base Attack/Grapple: +18/+35
Attack: Claw +30 melee (2d8+13)
Full Attack: 2 claws +30 melee (2d8+13) and 2 wings +28 melee (2d6+6) and bite +28 melee (4d6+6 plus poison plus disease) and tail slap +28 melee (2d8+6)
Space/Reach: 10 ft./10 ft.
Special Attacks: Constrict 2d8+26, fear aura, improved grab, spell-like abilities, summon devil
Special Qualities: Damage reduction 15/good and silver, darkvision 60 ft., immunity to fire and poison, resistance to acid 10 and cold 10, regeneration 5, see in darkness, spell resistance 32, telepathy 100 ft.
Saves: Fort +19, Ref +19, Will +21
Abilities: Str 37, Dex 27, Con 27, Int 26, Wis 26, Cha 26
Skills: Balance +10, Bluff +29, Climb +34, Concentration +29, Diplomacy +10, Disguise +29 (+31 acting), Hide +25, Intimidate +31, Jump +40, Knowledge (arcana) +29, Knowledge (nature) +10, Knowledge (the planes) +29, Knowledge (religion) +29, Listen +29, Move Silently +29, Search +29, Spellcraft +31, Spot +29, Survival +8 (+10 on other planes, +10 when tracking), Tumble +31
Feats: Cleave, Great Cleave, Improved Initiative, Iron Will, Multiattack, Power Attack, Quicken Spell-Like Ability (fireball)
Environment: A lawful evil-aligned plane
Organization: Solitary, pair, team (3-4), or troupe (1-2 pit fiends, 2-5 horned devils, and 2-5 barbed devils)
Challenge Rating: 20
Treasure: Standard coins; double goods; standard items
Alignment: Always lawful evil
Advancement: 19-36 HD (Large); 37-54 HD (Huge)
Level Adjustment: —
A pit fiend’s natural weapons, as well as any weapons it wields, are treated as evil-aligned and lawful-aligned for the purpose of overcoming damage reduction.
Constrict (Ex)
A pit fiend deals 2d8+26 points of damage with a successful grapple check.
Disease (Su)
A creature struck by a pit fiend’s bite attack must succeed on a DC 27 Fortitude save or be infected with a vile disease known as devil chills (incubation period 1d4 days, damage 1d4 Str). The save DC is Constitution-based.
Fear Aura (Su)
A pit fiend can radiate a 20-foot-radius fear aura as a free action. A creature in the area must succeed on a DC 27 Will save or be affected as though by a fear spell (caster level 18th). A creature that successfully saves cannot be affected again by the same pit fiend’s aura for 24 hours. Other devils are immune to the aura. The save DC is Charisma-based.
Improved Grab (Ex)
To use this ability, a pit fiend must hit with its tail slap attack. It can then attempt to start a grapple as a free action without provoking an attack of opportunity. If it wins the grapple check, it establishes a hold and can constrict.
Poison (Ex)
Injury, Fortitude DC 27, initial damage 1d6 Con, secondary damage death. The save DC is Constitution-based.
Spell-Like Abilities
At will—blasphemy (DC 25), create undead, fireball (DC 21), greater dispel magic, greater teleport (self plus 50 pounds of objects only), invisibility, magic circle against good, mass hold monster (DC 27), persistent image (DC 23), power word stun, unholy aura (DC 26); 1/day—meteor swarm (DC 27). Caster level 18th. The save DCs are Charisma-based.
Once per year a pit fiend can use wish as the spell (caster level 20th).
Summon Devil (Sp)
Twice per day a pit fiend can automatically summon 2 lemures, bone devils, or bearded devils, or 1 erinyes, horned devil, or ice devil. This ability is the equivalent of an 8th-level spell.
Regeneration (Ex)
A pit fiend takes normal damage from good-aligned silvered weapons, and from spells or effects with the good descriptor.
Now...
Running the 4e Pit Fiend should be relatively easy. It has several abilities which explain itself, its summoning requires you to know about two other types of devil to use effectively (one of which is a minion and thus dead easy to know), and it's obvious what it can do.
Running the 3.5 Pit Fiend is not quite so easy. Most abilities require you to look up what they do, unless you know by heart what exactly blasphemy, create undead, fireball, greater dispel magic, greater teleport, invisibility, magic circle against good, mass hold monster, persistent image, power word stun, unholy aura and meteor swarm do. Using its summoning ability requires you to know about six other demons, most of which are comparable in complexity to the pit fiend. What it can do is not always immediately obvious. Did you notice it will cast Fireball every round for free? How much power attack penalty will you take? Do you fully understand the consequences and systems of improved grab?
If you like managing this kind of situation (and there's a good chance you might, I certainly did for a while before I grew weary of it), 3e will be a good game for you. But my own preference by now should be obvious.
