In this theory I won’t tell you who exactly Luffy’s mother is, but I’ll try to bring out her personality. First, let’s see “how family works in One Piece”.
So, Vinsmoke Judge wants to create a strong army using his own children and Judge had removed all of his children emotions before they were born. Unfortunately, Sanji have emotions like his mother and expresses what he want not like Reiju (she didn’t want her brothers bullying her like they did to Sanji)
Sanji’s personality is almost the same with his mother.. Sora was a very kind and caring woman, with great strength of character. She loved her children and was fiercely protective of them, believing that they should grow up with normal human emotions and not as cold killing machines. As a result, she did everything in her power to resist her husband’s experiments on their sons, to the point of sacrificing her own life. So Sanji inherited his personality from Sora.
I’m not really sure in which way Sanji inherited his personality from him. I think Sanji inherited his body endurance from Judge.. but it’s so complicate to see their equation since Sanji’s power and dream come from his truly father Zeff.
She inherited her personality a bit from her mother but she can’t express it because she’s afraid of her brothers and father.
Ichiji, Nichiji, Yonji
They didn’t inherit anything from their parents’ personality even from Judge because you can see that Judge even cries when the wedding is becoming a disaster.. that’s because Judge removed their emotions.
Sanji and Reiju personality inherited from their mother.
No one inherited personality from Judge.
Sanji gets his ability and dream from Zeff.
Now with Luffy’s Family:
Monkey D. Dragon
Dragon looks like a truly a Leader from what we’ve seen. Revolutionary Army is doing his job carefully.. so Dragon looks clever.
His aura looks like Gol D. Roger.
Monkey D. Garp
He’s supportive person. He loves his family. He’s loyal with Marine (but Family first).
Monkey D. Luffy
Different with Dragon, Luffy looks stupid xD but sometimes he’s cool, and clever too especially in fights..
He lives freely, he’s stubborn and he always do something reckless that could make big big trouble.
Luffy is almost the same like Garp and Dragon but still.. he has different personality with them and could be that he inherited some traits of his personality from his mother:
– he always do something reckless
– he’s stupid but funny
– he’s creative
– he’s stubborn
In their family I believe Luffy’s mother have this personality too:
– she lives freely (do what she wants to do)
– she takes care of her family or nakama
– she lives with no regrets
*Theory by Denref