Kayla Black is the sister of Max Black and the only superhuman employed by the United States under the codename Blue Star.
Born and raised in Chicago, the middle child of a policeman  , Kayla had a troubled relationship with her family: her older brother died when she was a teenager, her younger brother Max bounced from one lost job to another, and she was discriminated for being openly lesbian.
After Max became Quantum, she at first tried to stay out of the superhero business but later volunteered for a process to give her the same powers of her brother. This was partially successful, giving her more limited powers; she remains employed by the United States, keeping her identity a secret to the general public.
Kayla's powers mimic those of Quantum; since her body isn't saturated with the energy of the Heart Of The Universe, though, she's apparently unable to access the full range of his abilities (most notably, she can't transform her own body into energy).
Energy generation: Kayla is able to generate energy from her body in various forms, from laser to radio waves to pure destructive force (typically with a blue color). Unlike Quantum, she doesn't seem to generate energy by converting her own mass, however the process can be tiring if she needs to create too much energy too fast.
Energy senses: Kayla can see beyond the visible spectrum and she can hear radio waves
Energy absorbtion: Kayla can absorb external energy into her own body
Blue Star suit: based on Noriko Null's design for the Excess and Overkill suits, the Blue Star costume regulates Kayla's powers and gives her the ability to fly. It's also equipped with advanced communication devices.
Human body: Aside from her powers, Kayla's body is human, giving her the same vulnerabilities of any other woman.
Anti-neutrino fields: Quantum's energy form can't pass through areas shielded by anti-neutrino fields, and he can't transform into the same.
- Beyond The Impossible #8, "Breakfast with the goddess": learns Max has powers
- Beyond The Impossible #50, "Unfinished business": consents to the procedure to give her powers
- Beyond The Impossible #73, "The Cursed Daughter": fights Eris
- Beyond The Impossible #98, "Hope and fear": loses her powers after the fight with Abyss
- Beyond The Impossible #124, "Genies and mothers": receives the new Blue Star suit
- Beyond The Impossible #182, "Never forget a face": fights Scarab
- Beyond The Impossible #240, "Cold Front": revealed to live in Colorado with her girlfriend