Leaf

Leaf (Full name Lephina Delia Ketchum, formerly Sakaki) is the younger twin sister of Red and older sister to Ash. As a young child, she wore her brown hair cut extremely short, which she grew out to a bobcut by the time she was ten. By fifteen, she was wearing her hair past her shoulders. She has warm brown eyes, a slender build, and is 5'11 when 15.

Early life
Born to Delia and Giovanni Sakaki in Viridian City alongside Red, Leaf was very fond of her father and wanted to be like him. She often shadowed him when he was home, admiring the shiny Pokémon he had. She decided when she was older, she would be a shiny hunter, too.

When she was 4, her parents split, although they did not formally divorce. Delia took the twins and moved them to Pallet while pregnant with Leaf's younger brother, changing all of their last names to be her maiden name. Leaf would be the only one of her siblings to remember her father.

Drowning
When Leaf was five, she discovered a scarf in the attic, dark gray with a letter "R" in red. Recognizing it as her father's, she began to wear it when she missed him over the next few years.

When she was nine, Delia and Daisy Oak left the children alone to play outside while they went shopping in the neighboring city. It was early spring, and the snow and ice were beginning to melt. Leaving their younger siblings on the river bank, Red, Leaf and Blue went to play on the frozen river. Stealing Leaf's scarf, Blue threw it a ways away on the ice. Leaf, determined to get her most prized possession back, went to get it.

Falling through the weakened ice, Leaf became trapped under the water. Red dove in after her, but couldn't reach her as the current dragged her along. Blue ran for his grandfather, and with the help of a Wartortle he had with him, Professor Oak managed to pull her out after she had been trapped for almost ten minutes. Leaf was no longer breathing, and an ambulance was called for both her and Red.

Red suffered nothing more than mild hypothermia, but Leaf was in a brief coma. It was unknown if she would survive. Waking up three days later, she was alright after a long recovery, but she developed an intense fear of ice and Ice-types.

Journeying
Setting out with her brother and rival at age ten, they pulled straws to determine who would get what starters. Leaf drew last, and the only one left was Bulbasaur, but she was pleased with the outcome. Challenging gyms, she tried to convince herself she wanted to go for the championship, but her heart wasn't in it the way Red and Blue's were.

She didn't catch very many Pokémon, coming across them in other ways instead. She caught a Vulpix, then Red won her a Porygon from the Game Corner. Finding a talent for breeding Pokémon, she bred herself and Red Eevees - hers was shiny, and she evolved it into an Umbreon. She also captured a Ditto for breeding purposes, but it quickly became her favorite Pokémon and her best fighter.

It was breaking into Rocket's hideout that made Leaf find her last Pokémon. In the labs were Pokemon being tested on - one was a very ill shiny Castform, permanently stuck in Rainy Form due to an experiment gone wrong. Figuring out it was sick due to a buildup of the hormone that would normally cause it to shift forms, she nursed it back to health and began giving it daily injections to clear out the buildup. Her Castform cannot feel aggression due to a damaged amygdala and is not used in battle.

Finding and healing Castform led Leaf to pursue her true calling - becoming a Pokémon Professor. This is the path she would pursue until she was 18, when she graduated and became one.

Trivia

 * Leaf, despite not being a champion, is ranked as one of the best trainers in the world.
 * She is the best Pokémon breeder in Kanto and breeds shinies for its elite to pay for her education.
 * She is hopeless for cute boys and flirts with every one she meets.
 * She tends to speak in a frantic rush with few pauses.