Era of Monsters: https://www.era-games.com/era-kaiju/

The world you knew is gone.
What remains is a battlefield where titans rule. Steel cities crumble, oceans rise, and the ground itself shakes with every step you take.

Since you awoke, you had only one purpose: conquer what remains.
Each Kaiju is a rival, each clash a test of dominance. Territory is survival, and only the relentless will endure.

The age of humanity has ended. The age of monsters has begun.