Dark Phoenix (CR 15)

This immense bird seems to be made of living black and purple flame. It spreads its wings and gives vent to a musical cry as it takes to the air. 

XP 51,200

NE Gargantuan magical beast (fire)

Init +11; Senses darkvision 60 ft., detect magic, detect poison, low-light vision, see invisibility; Perception +37

Aura shroud of hellfire (20 ft., 4d6 hellfire, DC 25)

DEFENSE

AC 28, touch 14, flat-footed 20 (+7 Dex, +1 dodge, +14 natural, –4 size)

hp 210 (20d10+100); regeneration 10 (cold or good)

Fort +17, Ref +19, Will +14