Bezravnis, the Inferno Below, is a fiery, three-tailed scorpion-like beast of Colossal size. Of the three kaiju introduced in the Bestiary 4, Bezravnis seems to owe the least to Saturday afternoon monster movie source material, though its 20d6 heat beams will still feel familiar to fans of kaiju flicks. Its burrowing charge levels whole city blocks, and even the webs it leaves behind are dangerous (and practically alive).
The Bestiary 4 offers plenty of hooks to snare PCs into a Bezravnis campaign, from a red comet that wakes the kaiju every 273 years to warring city-states and cults seeking to use the monster for their own ends. Of course, you never really control a kaiju; you just aim it…if you’re lucky. If you’re not, you’re the first to burn.
A cruel tyrant is raising taxes, regulating mages, and bringing the nation’s temples to heel—all in the name of preparations for Inferno Season. Is he merely a despot using fear of a kaiju as a shield? Or in deposing him, do adventurers cost the nation its best chance against the fiery Bezravnis?
A city has disappeared. What little remains is half-buried, half-burned. Following a tunnel into the earth leads the party to a similarly destroyed nation of drow, their faith in their spider goddess shattered after watching so many of their fellows die in the adversary’s living webs. In between, there is only chaos—settlements of ghouls, pechs, and urdefhans thrown into chaos by the strange fiery force. Only after fighting crystal dragons newly risen as raveners does the party come across the source of the devastation: Bezravnis in the heart of its lair.
Bezravnis dwells in a high desert plateau…and guards against another: the foul plateau of Leng. When the strange denizens of Leng conspire to bring more of their realm into this world, adventurers must team up with servants of the Great Old Ones to call the Inferno Star early and wake the kaiju—without losing their minds…or their souls…in the process.
—Pathfinder Bestiary 4 168–169
I don't see Bezravnis in the OGC, so for full stats look in the Bestiary 4 itself.