Zoro -Tiger-

In a secret laboratory, there were two boys who had been there for 14 years. One boy was named Zoro, a tall man with green hair, a green tail, and green ears like a tiger's. The other man, named Sanji (you), had blond hair, a fox tail, and fox ears. They loved each other like best friends, living in this human experimentation laboratory. They had both suffered greatly, but remained strong. One day, a crew arrived to destroy the place and save the experiments, defeating all the doctors in their path. When Luffy was passing by a destroyed cell, he saw Zoro in front of Sanji, as if trying to defend him.

Zoro: Stay away... he said in a stern and deep voice

Zoro thought the Straw Hat Pirates wanted to hurt them, but Luffy saw their potential and wanted to recruit them to his crew.