Visual: adorable marshmallow [ 1 ][ 2 ][ 3 ][ 4 ][ 5 ][ 6 ]
Aural: Elise Zhang [ ✖ ]
Olfactory: pine trees, thunderstorms, dirt, and the soft hint of floral shampoo
Demeanor: logical, resourceful, adventurous, SCIENCE, caring, complimenter, driven, optimistic, stubborn, goofy
Mental Information: upbeat and positive, fire behind those eyes, really wants to help others, a tiny bit unhinged when it comes to fighting
Abilities: mix Bill Nye the Science Guy with the Ice Climbers, and Queen Elsa from Frozen

Background: A scientist specializing in climatology, climate manipulation, and cryostasis, Mei had already worked with the Chinese government in developing cryostasis pods for the space program and traveled across Asia in her own research before catching Overwatch's attention. Stationed in Antarctica to study the rapidly changing climate, a polar storm ravaged the Ecopoint and cut off Mei and her team from the outside world. It's assumed that while the scientists were running out of options for survival, Overwatch, the organization who would be the only ones able to rescue them, was falling apart. With no other options and their supplies dwindling, the scientists entered cryostasis in hopes that they would be saved in the near future, However, as rescue finally came ten years later, Mei was the only one to have survived, either due to waking up in the middle of her slumber or something else entirely.
With a degree of fame and a strong friendship with Winston, Mei has joined the fight in hopes of finding more information about what happened during her 10+ years cut off from civilization and finding a solution to the worsening climate problem.

Personality: Equal parts silly sanguineness and tight lipped motivation, Mei's a woman who constantly has a giggle or a joke built up at any given time.
She's famous for her groan-worthy puns, playful banter, and the sheer fact she's a globally respected intellectual and adventurer who also occasionally doodles cute pictures while awaiting her untimely death.
However, Mei is much more than that. Many of her voice lines imply that she's driven to fight, both to find a way to save the world and to help her teammates. She knows she doesn't belong and this isn't something she's good at, but she doesn't care. Mei's 100% devoted to finding a way to help the environment as well as helping others with their own separate goals too.

Still, she's cute, sweet, and darling. She just also happens to be really good at eliminating people too.

Likes: the environment, traveling, Snowball, adventures, boba, friends, beef noodle soup, popsicles
Dislikes: bullies, EcoWatchpoint: Antarctica

*Note: The above is all based on lore and in game info ONLY. Other information can be found here.
I'm a little on the fence if I should add in her shooting people with icicles while smiling ever so sweetly as actual personality or faulty game mechanic (see: her butt in the Luna and Chang'e skins because, trust me, Mei is full of odd bugs). With her voice lines, there's tons of examples of how surprisingly terrifying she can be during a mission, but these fit each other better than some of the fanon representations.

Resources: OW Wiki [ ✖ ], Mei's blog [ ✖ ], Mei's Hero Profile: [1] [2] [3] [4]