Jor-El and Lara-Var
Due to convergent evolution, Kryptonians were near-exact genetic duplicates of Terran humans. Owing to the greater age of their race, Kryptonians were further along the evolutionary path; they lacked the body hair and toenails of their Terran cousins, and their physiques were more robust, with a powerful immune system and healing factor enabling an average lifespan exceeding 200 years. They also possessed charcoal skin tones, an adaptation enabling them to withstand the ultraviolet radiation of their red dwarf sun.
Kryptonian society was completely egalitarian. With rare exception, sons were born into the houses of their fathers, daughters into the houses of their mothers. Though a sexual race, Kryptonians relied on artificial "birthing matrices" to reproduce; natural gestation/birth was considered an inefficient primitive practice and was almost unheard of by the time of their demise.
Genetically bound to their planet, the population of Krypton could not relocate en masse to Earth in the face of their world's destruction. Instead, they created 144,000 genetically modified embryoes, tailored to enhance their resemblance to Terrans and grant them abilities which would make them living gods on Earth. Of these 144,000 "new" Kryptonians, only a handful survived to make it to their new colony and grow to maturity. Among them was Kal-El, biological son of Jor-El, scientist, and Lara-Var, librarian.
Superman/Kal-El (1938)
In the mid 1930s, between leaving Smallville and leaving America to serve as an ambulance driver for the Lincoln Battalion in the Spanish Civil War, one of Kal's jobs during the Great Depression was as the circus strongman "Samson". The outfit he wore as Samson was a basic affair, dominated by dark colours. It consisted of a long-sleeved shirt & tights, both made with navy blue wool. Over the tights were worn blue trunks held up by a black leather belt. Over his feet were worn black leather boot-sandals.
Upon returning from the war and settling in Metropolis, Kal prevented an experimental jet airplane from crashing, in plain sight of a large crowd of onlookers in broad daylight. Heeding the advice of his late father, Jonathan, Kal decided to adopt a new public identity. Taking his old strongman outfit out of storage, he had his mother, Martha, sew a black Kryptonian S-shield on the chest. Embracing the name the press had given him, he made his official public debut as Superman, the world's first costumed superhero.
Kal only wore this costume a few short months before it was destroyed in his climactic confrontation with Lex Luthor's red kryptonite-enhanced henchmen, Team Luthor.
Superman/Kal-El (1939)
Inspired by the flag of the CNT-FAI, Kal decided to incorporate red into his next suit. The black boot-sandals were replaced with red boots with black trim. The blue trunks were replaced with red ones. The S-shield was made red/black. Following Lana Lang's advice, he added a voluminous red cape to the costume.
Clark Kent/Kal-El (1939)
Kal at the time he joined the Daily Planet staff.
(Tried as I might, I couldn't get the proportions to look right, so I quit in a huff of frustration. Maybe I'll complete it someday. Probably not.)
Superman/Kal-El (1944)
Once America entered World War II in 1941, the Daily Planet assigned Kal to serve as a war correspondant overseas. Touring both Europe and the Pacific, Kal served dual roles, reporting the news as Clark Kent and assisting the allied troops against Axis forces as Superman. During the course of the war, his cape was lost and he took to wearing standard-issue US Army boots.
Superman (1971) &
Clark Kent (1971)
In 1947, Lex Luthor found himself to have malignant tumours. Due to improper shielding, he'd contracted radiation poisoning from the green kryptonite which powered his warsuit. A fugitive facing charges of treason for collaborating with Nazi and Soviet scientists before/during World War II, his cancer terminal, Luthor fully commited himself to defeating his hated enemy, the Man of Steel. Constructing an android simulacrum powered by black kryptonite, Luthor set it against Kal. During the course of the battle, the Lexdroid self-destructed, bathing Kal in black K radiation, splitting him into two separate individuals: an amoral Superman and a spineless Clark Kent.
Though a kind-hearted soul by nature, this new Clark was a strict conformist and highly superstitious, lacking gumption and conviction, defaulting to passivity when faced with the slightest adversity. As a result, both his career as an investigative journalist and his marriage to Lois Lane suffered. After trying three fruitless years to adjust to life with only half the man she had fallen in love with, Lois filed for divorce in 1950. Another consequence of his exposure to black K was the loss of his Kryptonian abilities, which had transferred wholly to his bolder half. Now a mere human, he began to age like one. However, it wasn't all doom and gloom for Clark. He managed to reconnect with Lana, who'd recently come out of her own failed marriage with Pete Ross. Unlike Lois, Lana was able to see past Clark's handicap, recognizing the gentle soul she'd been smitten with as a teenager. By 1953, the two divorcees were married. A year after that followed a daughter, Karen Kent. And though their marriage had disintegrated, Clark and Lois were able to remain friends, becoming co-news anchors on WGBS-TV in 1971.
Formally renouncing anarchism, Superman ingratiated himself to the US government. From 1947-1961, he served as their pawn, participating in the Korean & Vietnam Wars on behalf of America.
In 1958, Superman travelled to Universe 29, an "imperfect" counterpart of Universe 1 inhabited by "bizarre" duplicates of Universe 1 residents. Here, in his fateful encounter with his twisted twin, he was first exposed to blue kryptonite. Exposure to this alien kryptonite increased his powers tenfold, giving him the strength needed to defeat his opponent. Upon returning to Universe 1, he had a large crystal of blue K synthesized and began habitually bathing in its radiations, further augmenting his powers.
After three years of constant exposure to blue K radiation, Superman was bestowed a vast repertoire of godlike abilities. Following a brief, bloodless war with the world's military might, Superman seized command of the world's governments. Declaring himself High Councilor of Earth, he centralized control under the authoritarian socialist One Earth Regime enforced by his Superman robots and deputized superheroes.
In contrast to his sinister transformation, Superman redesigned his costume to feature even brighter colours. The black trim on the boots was replaced with yellow. A yellow border/outlines were added to the S-shield. Finally, a yellow/black S-shield was added to the cape. Sometime after 1958, spandex replaced wool as the fabric used in these costumes, which in turn was replaced by Unstable Molecules before the end of the '60s.
Kara-Re (1959)
Wegthor was the sister planet of Krypton. Terraformed and colonized by Kryptonians long millennia past, Wegthor and Krypton orbited each other, giving the double planet a day/night cycle in the close orbit around their sun.
Following confirmation of Jor-El's findings on the stability of Krypton's core, it was determined Wegthor, too, would perish in the inevitable cataclysm, sterilized by hard radiation. Like their Kryptonian kin, the Wegthorians were genetically bound to the biosphere of their double planet, preventing them from evacuating to Earth. But there was one slim chance at survival, if a force field of sufficient coverage/strength could be established around Wegthor to mitigate Krypton's blast.
Twenty-odd years passed. As the hour of Krypton's doom neared, as much of the Kryptonian population as Wegthor could support was relocated to the sister planet. As Krypton's core detonated, boiling the planet down, Wegthor was buffeted in a wave of kryptonite radiation. The force field around Wegthor held, providing enough protection to prevent complete holocaust. Still, Wegthor was devastated. Much of the planet irradiated, land became uninhabitable and inarable, bringing about mass extinctions and human deaths.
Kara-Re, genetic offspring of Kala-Re and In-Ze, was born in Argo, Wegthor's last remaining city. Among the neo-Kryptonian supermen, it was hoped she and her peers would be better able to thrive in this harsh world than their parents. Unfortunately, it wasn't so; they were even more susceptible to the kryptonite radiation infusing their environment. Kara eked out an existence for fifteen years, sick from radiation poisoning and malnourishment, until the last of the world's resources ran out, forcing the remaining survivors into suspended animation.
Superman visited the Rao system in 1959, curious to find Kryptonian artifacts. The Man of Tomorrow arrived on Wegthor, finding the facility housing the sleepers. He'd come too late to be any help for most, as all but Kara's cryo-chamber had failed in the intervening decades. Superman revived Kara and took her with him back to Earth, to his Fortress of Solitude in the Antarctic. There he kept her, nursing her back to health, teaching her about her new home, gauging her potential as both an ally and a mate.
Kara-Re (1961)
For close to three years following her arrival on Earth, Kara wore a biosuit to assist her kryptonite-weakened body in absorbing background radiation, invigorating her in a fraction of the time it would've taken her body to recuperate on its own.
Supergirl/Kara-Re (1962)
Kara spent almost three years as Superman's protege, covertly serving as his "secret weapon" as his plans for world domination ramped up.
After he established the Regime, the Man of Tomorrow revealed Kara to the public as Supergirl, his second-in-command and chief enforcer. Her role almost came to a premature end when the Superman Revenge Squad, led by Luthor and Bruce Wayne, attempted a coup. The Girl of Steel made short work of their men, but was laid low by the radiation of Luthor's kryptonite heart. Fortunately for her, the billionaire-turned-cyborg had bigger fish to fry, and was content to leave her incapacitated while he unsuccessfully went to tackle her boss.
Supergirl/Kara-Re (1971)
In 1971, Superman, having grown bored and listless in his role as High Councilor, decided to leave Earth. After transferring all power to Kara, he departed, seeking new and greater challenges amongst the stars.
Kara, who'd come to doubt the morality and efficacy of Superman's authoritarian methods, began making reforms in his absence. Over the next fourteen years, the Regime was gradually dismantled. Workers' councils and trade unions, outlawed with the imposition of the Regime, were restored. With the full cooperation of indigenous peoples, borders were redrawn, with nations divided into autonomous municipalities based on direct/liquid democracy. Many of these territories embraced libertarian socialism, operating by anarchist or Marxist principles, while others reverted to laissez-faire capitalism.
Superman/Kal-El (1985)
In 1985, Superman and Clark were finally merged back into a single individual. While the superpowered Superman hadn't aged a year in the decades they were separated, the non-powered Clark had. This had a noticeable effect on the reconstituted Kal, as not only did he possess a middle-aged Kryptonian form, but his powers had been significantly decreased, though not to their original pre-blue K levels.
Superwoman/Kara-Re (1985)
In 1983, Kara changed her alias to Superwoman, adopting a costume to reflect the new image she wished to convey to the world. She wore this costume up to 1985, the year Superman returned to Earth and remerged with Clark. For the first time, Kara met the undivided Kal-El. The two didn't have time enough to lay the ghosts of their past to rest before shadow demons from beyond the multiverse attacked Earth. Kara met with a tragic but heroic death saving the world.