Prehistoric: River God System

I am the river god! That's right, it's the sissy river god from One Hundred Thousand Whys! Now I'm panicking because I've traveled to a prehistoric world! There is a giant holding up the sky in front of me! He seems exhausted! Huh? The ax on his waist fell into the river of chaos! Say no more, I have to go to work! This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.