Drago

I think she is a strong character and would play a major role in the final saga. I think someone will die like Ace in War of the Best and this time his mother would help him just like Jinbei, The First son of the Sea did

There are already 10 members in the Straw Hat Pirates

1. Luffy

2. Zoro

3. Nami

4. Ussop

5. Sanji

6. Robin

7. Chopper

8. Franky

9. Brook

10. Jinbei (sorry if any of the spelling are wrong or incorrect)