Twilight's appearance consists of white, pink and vertical magenta stripes. Likewise, her eye is white. Unlike her siblings, her whole left eye occasionally glows white light instead of having a small red glow. She also has bright pink cheeks.
She wears a brown bikini top with a sakura flower printed on both sides. She wears a light pink flower. She also usually carries a big sunflower with her.
Twilight is a child-like robot with a feminine personality. Her personality appears much more gentle than her brothers, and her kindness is mentioned to be "a unique character trait", which seems to make her somewhat well-liked by her mother and siblings, though it can also annoy the others who are more openly "evil". She isn't good with gore and cruelness, which is why she is very often seen vomiting, with the vomit even turning different colors depending on situation.
In general, Twilight is considered "the cute one", with a tendency to do cute things like trying to solve the battle via rock-paper-scissors, or suddenly falling asleep, and liking flowers. She is also mentioned to dislike nasty things like gore and bugs. When the siblings begin their usual fighting, she often plays the mediator and seems to dislike arguing, but in the end, she always ends up joining in the fight. While often seeming very gentle and sensitive, she also has a tough side, like when she threatens to defeat all of her four brothers all by herself with her Exisal. She also hits Zack multiple times in the head with a frying pan in an attempt to fix his memory. She has referred to herself as a "strong, sensual woman" and says that she should't be underestimated because she's a girl.
Despite her kind demeanor, she can speak in mean manner just like her mother and siblings, and has a ruthless side. She tends to say things with somewhat mixed messages, beginning her sentence with kindness and then ending it with cruel indications. She may express worry towards others, but ultimately seems quite cruel like her other kind. Being a villain, she indeed seems to be evil and messed up even though sometimes appearing nice. Like all the cubs, she imitates her father by calling the heroes "you villains".
She is shown to act somewhat like a fangirl towards her mother and even appears to feel some attraction towards him, as she is the only one who enjoys her father licking her and even licks him back every time. She also agrees to have a romantic relationship with Zack after he begins to have severe memory issues, only reminding him about their family relation once and ultimately not really seeming to care. Due to his memory issues, Zack is seen acting abusive towards Twilight at times, making her sad but also feel bad for him due to his condition of his memory. She is shown to be the type who is happy as long as her partner is. When Zack finally returned back to normal, she mocked the heroes as he was no longer an ally to them.
- "We won't let you lay a hand on Mommy! We want Mommy to smile every day!"
- "Cry as loud as you want. I'll cry with you. We can spend the night together, crying... And the morning after, I'll write "goodbye" on your mirror in lipstick before I quietly leave."
- "It's the age of Boxcubs now! Out with the old, in with the new!"
- "Mommyyyyy! I love you, so please go back to normal!"
- "But...that's fine. As long as he's happy, I'm fine with that. Maybe not today, but someday...I'm gonna be happy too!"