Ancient Infernal Dragon CR 21

XP 409,600
LE Gargantuan dragon (evil, extraplanar, lawful)
Init +2; Senses dragon senses; Perception +38
Aura frightful presence (300 ft., DC 31)

DEFENSE

AC 40, touch 4, flat-footed 40 (–2 Dex, +36 natural, –4 size)
hp 406 (28d12+224)
Fort +24, Ref +16, Will +25; +10 vs. divination
Defensive Abilities inscrutable; DR 15/chaotic; Immune fire, hellfire, mind-affecting effects, paralysis, sleep; SR 32

OFFENSE

Speed 60 ft., fly 250 ft. (clumsy)
Melee bite +39 (4d6+21/19–20), 2 claws +39 (2d8+14/19–20), tail slap +33 (2d8+21/19–20), 2 wings +33 (2d6+7)
Space 20 ft.; Reach 15 ft. (20 ft. with bite)
Special Attacks breath weapon (120-ft. line, 20d10 hellfire damage, Reflex DC 32 half), commanding voice, crush, damnation flames, oppressive heat, tail sweep
Spell-Like Abilities (CL 15th; conc. +22)

1/day—fire storm (DC 25), infernal aide, meteor swarm (DC 26)
Oracle Spells Known (CL 15th; conc. +22)

7th (5)—dictum (DC 26), repulsion (DC 24)
6th (7)—antilife shell, dispel magic, harm (DC 23)
5th (7)—greater command (DC 24), scrying (DC 22), slay living (DC 22), true seeing
4th (7)—dimensional anchor, dismissal (DC 21), order’s wrath (DC 21), tongues
3rd (8)—blindness/deafness (DC 20), bestow curse (DC 20), invisibility purge, vision of hell (DC 21)
2nd (8)—cure moderate wounds, darkness, enthrall (DC 21), hold person (DC 19), silence (DC 19)
1st (8)—bane (DC 18), command (DC 20), forbid action (DC 20), sanctuary (DC 18), shield of faith
0 (at will)—bleed (DC 17), detect magic, detect poison, guidance, light, mending, read magic, resistance, spark (DC 17)

STATISTICS

Str 39, Dex 6, Con 27, Int 28, Wis 25, Cha 24
Base Atk +28; CMB +46; CMD 54 (58 vs. trip)
Feats Bleeding Critical, Combat Expertise, Critical Focus, Improved Critical (bite, claw, tail slap), Improved Initiative, Improved Iron Will, Iron Will, Lightning Reflexes, Power Attack, Quicken Spell, Weapon Focus (bite, claw)
Skills Appraise +40, Bluff +38, Diplomacy +38, Fly +15, Intimidate +38, Knowledge (history, local, nobility, planes, religion) +40, Linguistics +40, Perception +38, Sense Motive +38, Spellcraft +40, Use Magic Device +38
Languages Common, Draconic, Infernal, plus any 28 others
SQ planar infusion (300 ft.)

ECOLOGY

Environment any (Hell)
Organization solitary
Treasure triple

Infernal dragons delight in recruiting large entourages of overly ambitious mortals who gladly debase themselves in exchange for influence.