Lilly is the tritagonist of Alpha and Omega and the secondary tritagonist of Alpha and Omega 2: A Howl-iday Adventure, and Alpha and Omega: The Legend of the Saw Tooth Cave. She is Kate's younger sister, Garth's wife, one of Winston and Eve's daughters, Humphrey's sister-in-law, and Stinky, Claudette, and Runt's aunt.
Lilly is a slender wolf who has average length hair like Kate. In the beginning of the movie, she let her forelock hang over her left eye, but she swept it back in the end. Her face, mane, tail, paws, stomach, and the inside of her ears are pure white and her back, shoulders, eyebrows, and the outside of her ears are a very light pale grey. She also has beautiful violet eyes.
She is often more playful as she was when she was a pup unlike Kate who became mostly critical after Alpha School.
Lilly is a friendly, shy, fun-loving wolf and has a totally opposite personality from her sister, Kate. She doesn't have very much self confidence, until she meets Garth.
Unlike her sister, Lilly isn't so shallow as to instantly dismiss someone just because of bad howling. She takes an immediate liking to Garth when first she sees him, and wants to get to know him, offering to show him around her pack's territory. During their time together, she wins him over with her turtle impressions, and Garth tries to teach her some of his alpha moves.
When she shies after a little mishap, Garth pushes back her hair and compliment her eyes, leading her to start wearing her fur back, and start being a little more confident. She then helps Garth improve his howl and they howl together, realizing they're in love.
Lilly tearfully attends the wedding between Kate and Garth but is overjoyed when Garth proudly admits he fell in love with her.
While Lilly isn't as outgoing as the other omegas, she still has a sense of humor and likes to have fun in her own ways.
Lilly was first seen as a pup at the beginning of the film. She was running away from her sister, Kate, who had been practice hunting with Lilly as her target. Lilly did end up getting away, though.
As a teenager, she went with Kate to the Moonlight Howl where Kate was to meet her fiancé Garth but when she heard his howl, it sent her running to the lake. Lilly fell in love at first sight of Garth.
When Kate vanishes, the packs meet whereupon Lilly offers to show Garth around until Kate gets back and he agrees. Lilly and Garth get to know each other more, with Lilly doing impressions of turtles to make Garth laugh, and Garth trying to teach her some of his Alpha moves to build up her confidence, which leads to an embarrassing moment for Lilly where she falls and gets a big piece of tree bark on her back and then falls, Garth chuckles and says "A turtle, right?" then Garth brushes back Lilly's haircut which covers her eyes and is surprised by how beautiful Lilly's eyes are, which leads to Lilly having a little more confidence to wear her fur back.
Later that evening, Lilly teaches Garth how to improve his howl and they find they were meant to be. But then Garth notices his pack approaching, and tells Lilly to go immediately, fearing for her safety. Lilly runs to her pack to inform her father, Winston that the Eastern Pack is coming, but before the packs declare war, Humphrey and Kate return in the nick of time to prevent any bloodshed, whereupon Kate announces that she accepts marriage to Garth to unite the packs, which breaks Lilly's heart and makes Humphrey feel shocked and heartbroken.
In the morning, Lilly helps Kate prepare for the wedding by brushing her tail with a pine cone but Kate notices her sadness and that she's wearing her fur back. When the wedding starts, Lilly keeps silent in sadness as Garth and Kate go through the mating ritual, but to Lilly's shock-turned-delight, Kate backs out at the last moment, saying that she fell in love with an Omega, prompting Garth to do the same, declaring his love for Lilly. Tony starts a fight between the packs in an outrage, but a Caribou stampede interrupts the battle and Winston and Tony are forced to run to avoid getting trampled to death.
Winston and Tony are saved by Humphrey and Kate, but Kate seems to get trampled to death, leading Humphrey to lead the packs to howl a requiem for Kate, but she wakes up and they declare their love for each other. Winston and Tony agree to unite the packs under a marriage between Garth and Lilly, demolishing the rule of social class in the process, leaving Lilly and Garth overjoyed.
At Howling Rock, the packs, now united as one, howl as Garth howls much better than before and all the birds love him. Lilly compliments him as they nuzzle each other under the moonlight.
Lilly visits her family with Garth for a dinner, and it is revealed that they are now living in the tall grasses. When word of Runt's capture reaches the family, Lilly gives important valid information of the rogues plan to takeover and destroy there home. She volunteers to help out the alphas, but is told to stay with the pups.
Later, when Garth confronts the rogue wolves, they insult her and call her a "weak omega". Lilly rolls a log down a cliff and knocks out the wolves, asserting that she is a smart omega.
Lilly takes the Omega pups on a field trip to Shadow Forest, much to Tony's shock and displease.
- Lilly is named after the flower; the lily itself represents purity, innocence, and beauty.
- Lilly is pure white, yet none of her parents seem to have the genes for white fur.
- She only tells jokes about turtles. Many people wonder why.
- Even though the rest of her family are alphas, Lilly is rejected to the alpha position, though it's never specified why.
- Lilly wears back the fur that covers her left eye at the end of Alpha and Omega, but in Alpha and Omega 2, her eye is covered again.