Curse of the Gods by Charlie Nottingham

Even gods can be killed.

Nearly 300,000 years ago, Véa, Nix, and two dozen others created billions of souls. Without enough room on their home worlds to house them all, they brought them to Earth. They planned to return to Morduaine and Matriaza one day, once they defeated their ancient enemy.
But it isn’t the ruthless soul eaters they’re worried with this time. It’s Nix’s brother, Lux.
In a red stained rage, Lux burns Morduaine and Matriaza to dust.
Attempting to punish Lux for his sins sparks a war unlike any Earth has seen before. The war of the gods.
The former kings and queens hide wherever they can, fight as hard as they can, and pray they won’t lose their souls in the process.