Phyla-Vell is the younger sister of Genis-Vell, son of Mar-Vell, famed superhero. Phyla and Genis were conceived using cloned genetic material from their father Mar-Vell which their mother Elysius, an Eternal living on Titan, used to create her children. Genis was such a success that she decided to also create a daughter, and thus Phyla came into being. She was not given false memories of her father as Genis was, though some in-vitro psychic conditioning was used to 'raise' her so she could be decanted when fully grown.
Phylla possessed the natural powers of her father, including superhuman strength and durability, as well as energy blasts. She was always raised hearing about how great and successful a hero her brother was and so lived in his shadow despite never having met him. She herself was made to be a hero, and so that is what she became, operating simply under her real name since the family title of Captain Marvel was taken.
In time, she would receive some recognition for her work. Before the Guardians of Oa dabbled in green light, but after the failure of the Manhunters, they went through several other attempted methods. One of these were the Quantum Bands, which were created in something of a dangerous accident. unreliable, and requiring a calmness opposed to the sharply-honed instinct the Guardians desired, they rejected the bands as a mistake. The bands were passed into the possession of Eon, a being the Guardians respected, to dispose of.
Eon chose Phyla-Vell as a champion suitable for the bands, and she was redubbed as Quasar. Eon's gift came with a request: Go to Earth, as great events are unfolding there, and defend it from those who would do it, and reality, harm. When needed, he would call her back.
Phyla-Vell accepted this gift, and this assignment.
Phyla-Vell is an at-times impetuous, willful woman. She does not lust for blood, though she does care for victory. She is also deeply compassionate, being possessed of supernatural compassion, and cares deeply for the heroism she is expected to embody. She hates being compared to her brother, and tries to one-up his accomplishments even though they have never met. Her goal in life is thusly glory, though she wants only glory gained through "proper methods," as she has seen firsthand the effects of space tyrants and warlords trying to clothe themselves in splendor. Outside of being a hero, she has little time for a personal life, and little patience with most mortals who lack her abilities. Though like her brother she has a long string of romantic conquests, she, cosmically aware, has never been able to connect to another personally enough to stay. Perhaps she closes herself off for a fear of being hurt, in classic fashion.
Phyla-Vell has the natural abilities of her father and mother's carefully combined genes. This includes longevity, superhuman strength that can lift up to 1,000 pounds, firing energy blasts, flight and survival in space. She can also absorb a certain amount of energy attacks directed at her to power her energy blasts.
Phyla also has cosmic awareness though she has not given herself over to it completely, and thusly not been driven insane as Genis was..
Being created to be a hero, Phyla is a proficient and capable fighter versed in several different styles of space martial arts. She is also actively interested in cosmic politics, a such as they exist, and has a wide knowledge of many interstellar entities and threats. She's familiar with high technology, though she is not an engineer as such. She knows Eternal history and culture, and is coming to be familiar with Earth's.
As Quasar, Phyla-Vell possesses the Quantum Bands, a set of gold armbands set with four raised 'gems' that permit extreme manipulation of energy. The bands magnify her natural absorption and projection capabilities to a massive level, and also grant her the capability to form solid energy constructs and forcefields. Many shapes can be somewhat "preprogrammed" into the bands and be called up on command, such as the sword she very often carries. The constructs are incredibly strong and knives and blades that she creates are unnaturally sharp, capable of piercing at a sub-atomic level.
The bands also allow space travel and protect against telepathic attacks, though they block her cosmic awareness so long as she is in possession of them. The bands translate most languages for Phyla in place of the Awareness which simply understood them.
Lastly, they can transmute light around Phyla to make themselves invisible and seemingly change her clothing.
The Bands come at a price: The require a sense of oneness with the universe, though they consume this sense unto themselves. A wielder who becomes too wrapped up in their power will be destroyed. Phyla's cosmic awareness helps her to maintain the necessary calm to utilize the bands effectively.
Phyla also has some Eternal technology, including a small computer and communicator set that allow her to speak back to her family on Titan at superluminal speeds.
Phyla has a temper. It mostly comes out when Genis is somehow compared to her, but she can ge frustrated and impatient. The Quantum Bands will start punishing her if she falls too far into her temper's grip, and it isn't the sort of anger that would lead to the slaughter of innocents--but it can certainly lead her to foolish lapses of attention.
She is also good. Cosmic purity guides her hand, and she will not harm the innocent, nor will she suffer others to do so. She very rarely lies and isn't particularly good at doing so. Her ethical purity is a great source of pride to herself, and may hold her in check against better choices.