Sword lesbians unite, your outer space hero has landed and her name is Phyla-Vell! Though this might not be the first person you associate with the title of Captain Marvel, she was indeed briefly known by that name and has a fairly substantial claim to it as the daughter of the original Mar-Vell. Phyla-Vell might only have been Captain Marvel for the time it takes to blink, but she certainly made her mark on the title.
A well-meaning hero from a highly convoluted family, Phyla did what she could to be her own person, but her life just couldn't help but be influenced by her father's legacy and, as such, entrenched in all the Cosmic Marvel drama we know and love. In many ways, Phyla embodies her father's best qualities — she's hopeful, compassionate, brave, and rebellious. On the other hand, while her father was guided by a need for logic and perfection that was instilled upon him via his time with the Kree, Phyla goes by her gut instincts and doesn't always think things through. To say the least, her relatively short time in the Marvel Universe has been quite a wild ride, so buckle up.
Sword Lesbian: Origins
The Marvel Universe is known for being the home of some pretty strange happenings, but even by those standards, Phyla's origin story is pretty weird. Her brother Genis-Vell rebooted the whole entire universe with only a few slight differences, one of which being that he was no longer an only child, he now had a highly competitive sister. Much like Genis, Phyla was brought into this world through artificial insemination after their father's death. Their mother was Elysius, who was herself genetically modified to be the perfect mate for Mar-Vell. The Eternals get up to some extremely weird stuff, but again, creating a whole woman from scratch just so Mar-Vell could have an "ideal" girlfriend is pretty weird, even by their standards.
Elysius is, perhaps understandably in context to the culture in which she was raised, a bit of a perfectionist. Phyla spent much of her childhood training to become a better fighter than her brother, ostensibly so she could save the universe but perhaps more so that her highly critical mother would notice her. However, when they finally met up, their battle ended in a draw. She is disappointed in her brother and deems him unable to carry the title of Captain Marvel, and they fight over it, though they ultimately come to a truce of sorts. Phyla is immediately mired in the then-current Genis-Vell happenings, but she eventually meets Moondragon, and everything changes.
O Captain, My Captain!
Moondragon is the daughter of the once-human man who would eventually become the Guardians of the Galaxy's Drax the Destroyer. Originally appearing way back in Iron Man #54 (1973), Moondragon was initially known by the name Madame MacEvil, which would make for a great baby name if you happen to be in the market. Decades and a lot of bad decisions later, Moondragon goes through a breakup with Marlo Jones when Marlo returns to her husband Rick. She's going through a pretty difficult rejection period which comes to an end when Phyla-Vell arrives on the scene, flirting with her as they exit the book.
When the two resurface, they're a couple, attempting to visit the graves of Phyla's father and her brother Genis, who has since died. They are attacked by none other than Thanos, who uses Moondragon as bait. Though Drax, wary of Thanos' machinations, attempts to ignore Phyla's pleas to help his child, he eventually gives in and goes to her aid. Drax rips Thanos' heart out with his hand. Though Thanos does indeed recover, this is undeniably metal.
While all this is happening, Phyla teams up with Star-Lord and Nova to take on the villain Annihilus, who is attempting to destroy (almost) all life in the galaxy. She manages to get the immensely powerful Quantum Bands away from him, and after Annihilus is defeated and she is reunited with Moondragon, she decides to become the new Quasar.
In the Annihilation: Conquest - Quasar mini-series, we see more of her relationship with Moondragon, who helps her center herself by offering telepathic guidance. The Phalanx, an alien species which absorbs all organic matter into its hive mind, has defeated the Kree, and our dear queers are left to search the universe for the "savior" that can defeat them. During this quest, Moondragon transforms into a literal dragon, and can't change back. She assumes this means the end of her relationship with Phyla, but Phyla refuses to leave her. Though they do find the savior of the Kree, Adam Warlock, it comes at a price. Ultron murders Moondragon in her dragon form, and Phyla is devastated.
In the second volume of Guardians of the Galaxy, Phyla is reeling from Moondragon's death, and she makes it clear that she'll do absolutely anything to return her to life. She and Drax bond over their mutual grief, but neither of them deal with it very well. When she is offered up as a sacrifice to the monstrous Dragon of the Moon that Moondragon spent much of her life fighting against, Phyla makes a deal. She becomes the avatar of the cosmic entity known as Oblivion and attempts to kill her friend Adam Warlock, which is an arc that would have a lot of long-term story potential if she weren't almost immediately killed by Thanos off-panel afterward. Moondragon has visions of Phyla gestating in a cocoon, and we've seen some appearances of an evolved alternate universe version of her, but for all intents and purposes, Phyla-Vell currently remains deceased.
The fact that Moondragon and Phyla only appeared as a couple in a handful of issues and that not one but both of them died and at least one of them was transformed into a literal dragon while the other attempted to murder her own teammate is basically like if you gave the "bury your gays" trope a gallon of coffee, spun it around in a circle a bunch of times, then released it upon a comic book. Still, this is a ship with a substantial following. Though it is baffling that such a hugely popular character has been mostly left to flounder, we can only hope that means she'll be making a comeback in a big way, and we'll finally see some great stories with these two, in which both swords and dragons feature prominently.