Master of Mechanized Beasts

Your cultivation is higher than mine. What do I do if I can't beat you? Run? You're so behind the times! Ever heard of overwhelming your enemy with numbers? If I can't beat you, I'll bury you under an army of mechanical beasts! Legend has it that mechanical beasts were once a formidable fighting force in ancient times. But much of the core technology used to build them has since been lost. Mechanical beasts are still everywhere in the world today. But because of their limitations in speed, agility, and attack power, they can no longer be used in battle. They're only good for manual labor and transportation. The protagonist lives in this world at the tail end of the mechanical beast era. But after his modifications, these beasts, which have almost no combat ability, become powerful fighters. He even builds an army of mechanical beasts...