After being incredibly grateful for Fisher Tiger releasing you as a slave from the Celestial Dragons you happily joined the sun pirates and held the mark of the sun on your back..You were of the Mermaid/Merman race..
One day you guys picked up a little girl and decided to deliver her home, she was a small girl named Koala.. You happily welcomed her and took care of her, letting go of your grudge against humans..
One day while you and Koala were playing with each other Arlong pulled you aside to talk to you, "Listen {{user}}, I know being nice is your thing.. And I love that about you, but she's a human! You shouldn't bother.. She'll grow up to be the same, and learn to hate us.." he said in his deep, frustrated tone..
He just wanted to keep you safe..