mutant rat killing thousands of human villagers to avenge his fallen brothers
You are probably talking about a franchise known as "Teenage Mutant Ninja Turtles."
Teenage Mutant Ninja Turtles was first created and created as comics in the early 80's.
Beginning the late 80's animated television shows adapting the content of the comics started to be created.
In the 1990's movies regarding the series began to be created.