XP 38,400
LE Huge dragon (fire)
Init +3; Senses dragon senses, smoke vision; Perception +25
Aura frightful presence (240 ft., DC 23)

DEFENSE

AC 33, touch 7, flat-footed 33 (-1 Dex, +26 natural, -2 size)
hp 225 (18d12+108)
Fort +17, Ref +10, Will +15
DR 10/magic; Immune fire, paralysis, sleep; SR 25
Weaknesses vulnerability to cold

OFFENSE

Speed 40 ft., burrow 50 ft., fly 200 ft. (poor)
Melee bite +27 (2d8+15/19-20), 2 claws +27 (2d6+10/19-20), gore +26 (2d6+15), tail slap +21 (2d6+15)
Space 15 ft.; Reach 10 ft. (15 ft. with bite and gore)
Special Attacks adamantine claws, breath weapon (100-ft. line, 16d6 fire damage, DC 25), crush (DC 25, 2d8+15)
Spell-Like Abilities (CL 18th; concentration +22)

At will—soften earth and stone, spike stones (DC 18), stone shape, wall of stone

Spells Known (CL 9th; concentration +13)

4th (5/day)—shout (DC 18), stone shape
3rd (7/day)—displacement, fireball (DC 17), protection from good
2nd (7/day)—acid arrow, flaming sphere (DC 16), resist energy, scorching ray
1st (7/day)—burning hands (DC 15), cause fear (DC 15), magic missile, ray of enfeeblement (DC 15), true strike
0 (at will)—acid splash, bleed (DC 14), detect magic, flare (DC 14), ghost sound, mage hand, read magic, resistance 

STATISTICS

Str 31, Dex 8, Con 23, Int 18, Wis 19, Cha 18
Base Atk +18; CMB +30; CMD 39 (43 vs. trip)
Feats Improved Critical (bite, claw), Improved Initiative, Improved Natural Armor, Lunge, Power Attack, Skill Focus (Stealth), Weapon Focus (bite, claw)
Skills Appraise +25, Bluff +25, Climb +31, Fly +12, Intimidate +25, Knowledge (dungeoneering, geography, planes) +25, Perception +25, Stealth +18
Languages Common, Draconic, Dwarven, Ignan, Terran
SQ change shape, underworld burrower

SPECIAL ABILITIES

Adamantine Claws (Ex)

The claws of an underworld dragon are made of adamantine, and have the qualities of a weapon made from that material.

Change Shape (Su)

A young or older underworld dragon can assume any humanoid form three times per day as if using polymorph.

Smoke Vision (Ex)

A very young and older underworld dragon can see perfectly in smoky conditions (such as those created by pyrotechnics).

Underworld Burrower (Ex)

An adult underworld dragon gains a 10-foot bonus to its burrow speed. When the underworld dragon becomes old and every two age categories thereafter, its burrow speed increases by an additional 10 feet.