Simplify the following text for a Grade 9 native English-speaking person.
Original: He became friendly with the animals of the mountain , and later , after catching Shutendouji , the terror of the region around Mount Ooe , he became a loyal follower of Minamoto no Yorimitsu under the new name Sakata Kintoki .
Simplified: He became friendly with the animals and imaginary things of the mountain . Later , after catching the terror of the region around Mount Ooe , Shutendouji , he became a great follower of Minamoto no Yorimitsu under the new name Sakata no Kintoki ( å ç '' å