Nojiko

Nojiko is the adoptive sister of Nami (the two aren't related but were raised together by Belle-Mère).

Appearance
Her right arm is covered in tattoos, which she got to help Nami not to feel ashamed of her tattoo of Arlong's pirate logo. In the manga, she gave her bracelet to Nami. Her hair is light blue and seems to wear pink lip-liner.

Personality
Nojiko is Nami's level headed sister. She is highly supportive to Nami, her adoptive sister, and generous to Genzo, who she and Nami had seen as a father figure. Unlike her sister, she seemed to keep herself out of trouble, although she apparently had a habit of upsetting boys.

Nojiko always had a fairly content relationship with Bellemere and never saw a problem with being adopted by her stepmother. Unlike Nami, she was aware of the situation she was found in by her and she laughed alongside Bellemere about how Nami had been unaware of the bloodshed that happened around them.

Past Story
She had a tragic past in which everyone around her was killed in a battle between some Pirates and Marines. After the fighting had stopped she found a baby and began to wonder around until she came across Bellemere. Using what little strength she had, Bellemere pulled herself over to the the two children and to the delight of both Nojiko and Bellemere, the baby laughed seeming unaware of the bloodshed that happened.

Soon afterwards, Bellemere set sail for her home town with the two children and arrived back home during a storm. She handed over the two girls to the village doctor even though she was hurt. After all three were better Bellemere announced she was taking in the two girls Nojiko and the baby (who had been dubbed "Nami" by then), something Nojiko was apparently happen about.

Their life together was a struggle as Bellemere was poor. Being the elder of the two sisters Nojiko had everything bought for her first and Nami would end up with her hand-me-downs. After scolding Nami for denouncing them as a family causing Nami to run off, Nojiko was sent after her.

That same day Arlong invaded the island and found her home, Bellemere tried to fend the fishman off but was quickly subdued. When asked for the fee needed to stay alive, it turned out all the money Bellemere had would either save herself or her two daughters. Things would've been okay, as Arlong was unaware of the two girls' existence, but Bellemere gave it to her two girls as she would rather have died than not call herself a mother. To that end, Arlong shot her right in front of the eyes of her two adopted daughters, but not before Bellemere apologized to Nami for not being richer, and not being able to buy the girls whatever they wanted. With that, she said her final words to the girls: "I love you."

Present Story
In the present storyline, she saves Usopp and a boy called Chabo from the hands of the fishmen.

She reveals Nami's past to the Straw Hats. After trying to stop Nami from attacking Captain Nezumi, a Naval officer who tries to take the money Nami raised for her deal with Arlong, Nojiko was shot by him in the back. However, she survived. She also aided in the rescue of Luffy with the help of Genzo after Luffy is thrown into the ocean by Arlong with his feet stuck in a block of cement.

Current Events (Spoilers)
She is later seen after Nami gets her first bounty, apparently content with the idea that at least she is smiling in the photo.

Trivia

 * In a response to a fan about whether Kuina and Tashigi's names come from birds, Oda also mentioned that Nojiko's name too comes from a bird.