Humandrill

Humandrill (ヒューマンドリル) are a type of primate that Roronoa Zoro encouters in Kuraigana Island. They are highly intelligent creatures capable of imitating humans so much that they will mimic any trait they witness. If they were to see peace they would be peaceful creatures, however they had witnessed over seven years of war a violence, causing them to learn how to wield weapons and become bloodthirsty warriors.