A fatigued St George knocking out Cairax’s teeth and breaking his bones

St. George, the Mighty Dragon, pushed against gravity, shot up, and threw all his strength into a single punch. Dozens of oversized teeth sprayed out across the street as the monster’s jaw shattered. A second punch crushed its rib cage and he felt the shredded muscles of his arm howl.
He threw a third, fourth, and fifth, knocking the demon back with each one. Both fists came together and he felt its sternum crack.

Excerpt From Ex-Heroes, pg 447
Peter Clines
https://books.apple.com/us/book/ex-heroes/id585738407