Definitely Robin. Her past is really100x a heartbreaking story. A child in that age and a girl!!! that the whole town despise her because her DF ability,even her relative felt that way. To have a place she belongs to (Dr.Clover n friend) but annihilate in the end. To wants to meet her mother n thats why she studied history but in the end she just have a few minutes with her mother.... the 1st friend outside Dr.clover n friend that accept her (VA Saul),but died in front of her eyes.... The journey she spent from her tiny age till she's grown-up that full of betrayal... Its too much too bear!!!!! A child in that age!!!! Never knew what happiness is.... a really heartbreaking past ( I cry so much!). I just want to hug her n to finally say,"Its allright now."

But now,with Luffy n crew,she will experience what so called happiness n joy that she never experienced in the past. Thank you Luffy....