The People’s Heroes were one of the main known superhuman intervention team in the USSR, with their first documented appearance taking place in the mid-80s, during the early Gorbachov years and thus the last years of the Cold War.
Their first appearance occurred on the behalf of the president of Mozambia, an African country aligned with the Communist Bloc. The manipulative local tyrant, Edward Bentama, had ended up kidnapping an American citizen, Lynn Stewart - who turned out Black Lightning’s ex-wife, resulting in the arrival of the Outsiders (who, at that point, were no longer operating with Batman) in Mozambia.
Knowing that he lacked the means to handle superhumans, Bentama requested help from his Soviet patrons, arguing that the Outsiders were likely to discover some schemes implicating the USSr. The People’s Heroes were sent in, with the international mercenary known as the Bad Samaritan acting as an advisor and strategist.
Being much better prepared and getting a few lucky breaks, the People’s Heroes handily defeated and captured the Outsiders, though Black Lightning narrowly managed to escape. In particular, Hammer managed to defeat Geoforce in a brawl. Black Lightning arranged to ally himself with the underground opposition and free his comrades ; the People’s Heroes were caught flat-footed and defeated while scattered (Sickle being hit by a blast from Looker before being defeated by Katana; Hammer was apparently knocked out by Geoforce after a rather destructive brawl). This defeat hurt the credibility of the People’s Heroes with the Soviet government, in turn boosting the profile of the rival Rocket Red corps.
The next documented mission of the People’s Heroes occurred during the covert tug-of-war between US and Soviet intelligence, to score propaganda points using the dissident writer nicknamed Firebird. The Heroes clashed with a Suicide Squad team, which was suddenly reinforced with further operatives. Sickle clashed with one of the reinforcements, Captain Booomerang, who incapacitated her when one of the various boomerangs she Blocked with her weapon turned out to be an explosive one; Hammer was sent away by Black Orchid, who used the fact she could fly and he could not.The operation proved to be largely a failure for both sides, and the dissident was killed before she could be exfiltrated.
The People’s Heroes disbanded for a while under unknown circumstances when the USSR broke down. Apparently, the Ulyanov siblings parted ways with the rest of the Heroes - and the Russian intelligence community - and started getting involved in the international crime scene, at some point during the 1990s. They started receiving significant cybernetic modifications, enhancing their already solid abilities ; from intelligence accessed by Catwoman, it would seem that the enhancements implied abominable and dehumanising torture. Not only did they become considerably tougher but they became even meaner with a significant psychotic vibe, and over the decade developed a reputation as almost inhumanly ruthless killing machines, with a long string of heinous deeds in the files of various intelligence agencies.
Sickle was briefly seen in 2001 (still wearing her Heroes uniform, which seemed to still have its Soviet motifs), as part of the small army of female costumed adventurers and criminals assembled by Circe to conquer New York City. Hammer was not with her at this point.
A few years later, Hammer and Sickle reacted to a strong rumour spread by Hush among the underworld, indicating that the East End of Gotham was now open turf. The area was actually under the protection of Catwoman, but a much stronger group of super-criminals, led by Dr. Hugo Strange and including Hammer and Sickle, moved in. Vaguely suspecting the true situation one of the newcomers, Captain Cold, offered Catwoman to join the crew and rule over East End turf, since he had appreciated working with her in the past. Though it was a very near thing, Catwoman used elaborate deception and a large helping of luck to disrupt and defeat the plan; Hammer and Sickle were incapacitated by Catwoman and arrested by the GCPD.
From there, the siblings ended up in Federal custody. Eventually, an ambitious American civil servant and his Russian equivalent agreed to a discreet and unofficial exchange of superhuman operatives in order to take credit for recovering prisoners and advance their respective careers. The Ulyanovs were traded against a dozen of special operatives with muscular enhancements; however the swap went awry when the former People’s Heroes unexpectedly broke away from the heavy contraptions holding them immobile, slaughtered everybody present and commandeered a Russian gunship.
Since there was little point in flying to Russia, that country no longer being home, Sickle decided to instead go back to the US and visit some revenge on Catwoman. Apparently, they arranged to have a second round of cybernetic augmentation done somewhere on the way, using “Russian science” - perhaps a renegade Russian cyberneticist. They also further modernised their costumes - and made them redder in case anybody was missing the point.
They hit Gotham’s East End and soon found and subdued “Catwoman” - only to discover their prey was actually Catwoman’s teenaged friend Holly, wearing the Catwoman costume to save a baby who had been taken hostage by a Z-list supervillain, Blitzkrieg. Before they could kill her and move on, the real Catwoman came to the rescue, using a number of grenades and weapons stolen from a nearby SWAT team to Stun the pair, grab Holly and run away, letting the Russians run right into the SWAT when they recovered and gave chase.
The Russians plowed through dozens of cops, barely slowing down. Catwoman blew up Boris using Blitzkrieg’s weapons and he fell from fifteen stories high, but that did not stop him ; having smelled baby powder on Catwoman, Sickle sent her brother to her apartment to kidnap her infant daughter while she nailed Catwoman. Boris did so (apparently using some kind of superhuman movement power), and Sickle stopped fighting Catwoman after mentioning they were now after her daughter. The psychotic killer knew that her opponent’s only choice was to rush down, commandeer a car and speed to her apartment to save her daughter, since she could not know that Boris had already done the deed - and the sadistic Sickle’s plan was to have Boris leave the baby in the middle of the road after an angle so Catwoman would run over her own daughter.
This cruel plan underestimated Catwoman’s peerless reflexes and agility, however - not only did she manage to flip her car over her daughter instead of smashing her, but she also bailed out in mid-air and grabbed her. Even then, the Ulyanovs easily tracked her down, knocked her out and dragged her back to her home, where Sickle wanted to kill her daughter before Catwoman’s eyes, then kill her. Catwoman managed to Stun and defenestrate Boris using one of her special high-powered tasers, but was about to be killed by Natasha when Holly came in and shot Sickle by surprise with a special GCPD SWAT shotgun, knocking her off a window. Holly and Catwoman then ran away with the infant as an army of cops rolled in. They were apparently able to arrest Hammer and Sickle this time.
More recently, Sickle and Hammer were part of the second wave of costumed criminals deported to an alien world as a reaction to the World War III and other catastrophic events, including the murder of the Flash. They sided with the Luthor camp among the super-criminals, and seem to have been among those who eventually made it back to Earth, largely thanks to Luthor’s genius. For a brief time, Catwoman allied with them (since they were the people most likely to kill her, she’d rather keep them close to her) by arguing that Luthor had the means to go back to Earth, but would certainly not accept to save two Communists, but the alliance over that lie broke down pretty quickly.