Ivan Steranko is a large, muscular, blond-haired yet balding Russian man with a thick accent, gold tooth, and several scars on his face. Steranko wears a black suit with shoulder pads that each have two gold spikes on it, a black dress shirt, a red tie, an Ushanka with a yellow star on it, and on his fists two golden knuckle dusters, with a hammer on one and a sickle on the other. His most distinguishing feature is that he seems to be missing his right eye, having replaced it with a diamond studded prosthetic.
As Rocksteady, Steranko is a large humanoid mutant white rhinoceros with his shoulder pads (which assumed a different shape and sprouted a third spike) and the tops of his knuckle dusters melted onto his body. After this mutation, Rocksteady wears a tank top, brown bandoliers, and camouflage pants which somehow appeared on him after his mutation.
He describes himself and the Shredder as "old friends." He seems to take great pride in his collection. Steranko is rude and humorless, but is willing to be reasonable and make deals when the opportunity presents itself.
As Rocksteady he is even more aggressive and develops more fighting skills to match his new form. He even likes the name Michelangelo gave him.
The story of Ivan Steranko, and under what circumstances he came in contact with Oroku Saki as a business partner, is largely unknown. In "Enemy of My Enemy," He first appears to be close to the Shredder, given an offhanded mention that they're "old friends." He is first seen talking to the Shredder, albeit left unnamed, about a weapons deal. The Shredder does have the cargo searched just in case Steranko pulled any tricks. During the Turtles' fight with the Shredder, he is presumably knocked unconscious by the weapon that was meant to incapacitate the Shredder.
In "The Legend of the Kuro Kabuto." Steranko is revealed to collect ancient artifacts and is shown to have Excalibur and the Spear of Destiny in his collections; he also has the ability to tell the difference between a fake and real artifact. He was revealed to have some past history with master thief Anton Zeck, who at that time he was helping him with a vaguely defined job (allegedly accidental), and also is who shot out Steranko's right eye. Steranko hires Zeck to steal the Shredder's helmet, the Kuro Kabuto, from the Shredder to add to his collection. When Zeck meets up with Steranko in his helicopter, they discover that Leo had swapped it out with dirty diapers. Upon discovering this, Steranko vows to hurt Zeck for it.
In "Serpent Hunt," after the Kraang took over the city, Steranko and Zeck have been stuck in Steranko's hideout for months with nothing left to eat but cockroaches and ketchup. They devise a plan to escape the city: they would find the Shredder's "daughter," Karai, and trade her with him for a safe way out of the city, as the last thing they wanted was to be mutated by the Kraang like the other humans in the city. The plan however doesn't work as intended, as the Turtles released Karai; for the actions they committed, Steranko and Zeck are captured and brought to Shredder. After Zeck is mutated into a warthog for the attempted theft of the Kuro Kabuto, Steranko attempts to reason with the Shredder that he would be more useful as a normal human. Although it appeared that the Shredder was moved by the plea, Rahzar knocked him into the mutagen vat after Steranko tried to run. Due to the mutagen being filled with rhinoceros DNA, Steranko mutates into an anthropomorphic rhinoceros. After the mutated Zeck stated that the Foot Clan turned them into "freaks," they both bellowed out in pain, confusion, and anger.
In "The Pig and The Rhino," Steranko and Zeck are furious over their fate of becoming "freaks" and proceed to attack Shredder who easily combats the newly mutated duo. Once more, Saki orders the two to search for the mutated Karai and obey his commands or else suffer. When scouring a rooftop, Steranko convinces Zeck to abandon their mission and instead go with a new agenda: the elimination of the Ninja Turtles. Believing if the Turtles didn't interfere during the exchange from the last episode, the two would have escaped from the Kraang infested city. Splitting up, Steranko clashes against Casey Jones and Raphael at Argosy in a surprise attack. Due to Steranko's newly enhanced body, the rebellious duo are unable to hurt the Russian rhino and are knocked out and captured. After arriving at Coney Island due to Zeck capturing Donatello and April O'Neil and taking the former's T-Phone, the two scare off a frightened Karai and order for her arrival before the four hostages suffer. In an attempt to save them, Michelangelo attempts to distract the two with several mutant nicknames from several stands so Leonardo can rescue the others. When Mikey decides on "Bebop and Rocksteady" from a music van, Steranko takes an immediate liking to "Rocksteady" whereas Zeck can't stand his new, dumb nickname of "Bebop." Zeck's frustrations cause Michelangelo to discover the two have a Retro-Mutagen blaster; before Zeck fires at Mikey, Steranko tells his comrade it can cure them from their current state before arguing over who uses it first; as a result of the bickering, the others are freed and Karai aids the six, causing Steranko to accidentally destroy the vial and land in a ring throwing stand. While Don, April, and Casey battle Zeck, the other three Turtles rumble with Steranko aboard the roller coaster, using another retro-mutagen vial to trick him. The three are still unable to cause damage due to Steranko's enhanced speed when on the ride; in addition, when Raphael and Michelangelo attempt to double team him from the air, Steranko once more resists the duo. He also captures Mikey, demanding Leonardo to hand over the vial or he'll throw the youngest Turtle off the coaster. Leo is able to trick Steranko into throwing Mikey back over to him first; the "word" Leo gave on handing the vial is proven false, as Raph swings across to grab the vial, saying that he didn't give his word compared to his older brother. Leo is finally able to defeat Steranko, tricking him with one of the empty coaster seats before attacking him from another seat. The force of the impact causes the Russian rhino to finally be defeated; Zeck is also defeated as his boss lands on top of him. However, the duo escape into the night due to the six focused on the incurable condition of Karai, who bids the six farewell before disappearing into the water. Despite failing their personal agenda, the two do succeed at Shredder's mission where they capture Karai at an alleyway.
In "The Noxious Avenger", Baxter Stockman has given Bebop and Rocksteady orders off-camera to go searching for Reagent-X, a chemical necessity for the Mind Control Serum. While they find the chemical and a mutagen vial, the Turtles intervene due to the obvious van named after them outside. During the ensuing battle, Bebop throws the mutagen canister at Michelangelo who ducks it before the two escape; unbeknownst to everyone, Garson Grunge is hit by the canister and is mutated. Steranko later complains of continuously doing Stockman's errands; upon hearing of the mysterious "Muckman" from the news, the two decide to manipulate the new hero. Although Muckman clashes with them, Bebop and Rocksteady are able to convince him to help, blaming the Turtles for causing not only their condition, but Muckman's too. When the Turtles once again intervene, another fight ensues where Muckman is tricked once more to enter the lab run by Kraang technology. Realizing he's a slave, Muckman turns against the two, puking on the retrieved chemical to destroy it, causing Rocksteady and Bebop to escape once again.
In "The Deadly Venom," Rocksteady (without Bebop) appears in the beginning of the episode where he is tasked to fight the now mind-controlled Karai, who defeats Steranko with ease.
In "Attack of the Mega Shredder!", Rocksteady and Bebop are ordered by Saki to protect their lair as he senses the Turtles will attack yet again, warning them of severe punishment for failure. As he thought, the Turtles manage to make it into the catacombs before they're chased off by Rocksteady, Bebop, Tiger Claw, and the Shredder Elite. However, Shredder's livid by the Turtles getting so far, threatening everyone with punishment if it occurs again. Later, when Leonardo and Michelangelo attempt to infiltrate Stockman's lab to retrieve one of the Mind Controlling Worms, they're caught by Bebop and Rocksteady. As they prepare to mutate the two, Leo and Mikey are able to convince them to mutate them with the Shredder Elite, but by falling for their trick, Rocksteady and Bebop end up mutating the Shredder Elite into an amalgamation dubbed the Mega Shredder. After the Turtles, April, and Casey are able to destroy it, Rocksteady and Bebop face Shredder, who's furious over their foolishness; he leaves Tiger Claw to give them a fitting punishment, leaving Rocksteady and Bebop to run for their lives as Tiger Claw pounces at them.
In "The Fourfold Trap," Rocksteady is part of an elaborate trap, led by Karai, to capture the Turtles and April. It works with April now a prisoner with Karai, and the Turtles subjected to a torture fitting each of them. Knowing that Splinter will come to rescue them though, Rocksteady and the other henchmutants attempt to ambush and defeat him before he reaches Karai's command center, but Splinter easily overpowers and defeats them before continuing on his way to save his sons and April.
In "Annihilation Earth!, Part 2," Rocksteady catches April and Splinter when they infiltrate Shredder's lair to establish a truce with Saki against the Triceratons and save the Earth from destruction by the Heart of Darkness. At first, Shredder agrees, with Rocksteady proving his strength by going horn-to-horn with the Triceratons. However, Oroku Saki puts his vengeance over anything else, murdering Splinter before he can stop the Heart of Darkness, condemning the Earth to annihilation. Rocksteady embraces Bebop as the two of them are among the first victims to be sucked up by the Heart of Darkness' black hole before the rest of the Earth follows. The events are later reversed in "Earth's Last Stand," as Rocksteady is still alive and remains in service to Shredder.
In "City at War," Rocksteady and Bebop are seen guarding the entrance to Shredder's new hideout when Tiger Claw returns to report on the destruction of their weapons cache by Karai and the Turtles.
In "Broken Foot," after learning of the destruction of their money laundering operations and the arrest of Hun and the Purple Dragons by the NYPD, Rocksteady joins Bebop and Tiger Claw with defending Auman Chemicals from an attack by Leo, Karai, Shinigami, and their Foot Ninja. During the fight, Shinigami insults Rocksteady by calling him a dinosaur, angering him as he tells her he is a rhinoceros, before his attempt to tackle her causes him to miss and land on Bebop, who saves them from being crushed under one of the factory presses, but leaves them flying all over the place while Shinigami plants the explosives. After escaping the initial detonation of the explosives, Rocksteady and Bebop give pursuit of the Party Wagon in their van, where Rocksteady is frustrated when Bebop uses the machine gun built into the grill of their van to attack the Party Wagon when he normally does that, but after being attacked by one of the Party Wagon's stink bombs, Rocksteady deploys a pair of sickles from under the front of the van to dislodge one of the Party Wagon's rear tires and cause it to crash, but the Turtles escape before Tiger Claw can deal with them. Knowing that Karai will return to Auman Chemicals to take down the Footbot factory since that will be her next target, Rocksteady again awaits for her with Tiger Claw and Bebop, while the factory begins cranking out Elite Footbots to deal with her. When the Turtles, minus Donatello due to injuries, arrive to rescue Karai, Shinigami, and the Foot Ninja, Rocksteady engages them, where Mikey insults him by saying his mother wears combat boots, only for Rocksteady to retort that his mother does wear combat boots, before bowling over several Elite Footbots during his charge before crashing into Bebop as he was about to take revenge on Shinigami. After Karai destroys the factory and the Elite Footbots as well, Tiger Claw orders Rocksteady and Bebop to stop them, but Rocksteady only gets off a couple of shots before the Turtles, Karai, Shinigami, and the Foot Ninja escape, leaving Rocksteady to escape with Tiger Claw and Bebop before the NYPD and FDNY arrive to deal with the fire consuming the factory.
Powers and abilities
- Black rhinoceros physiology: As a result of his mutation, Rocksteady gained the body an anthropomorphic black rhino. As such, he has the natural abilities of a black rhino.
- Enhanced strength: Rocksteady's strength has been enhanced to the point where he is able to lift someone up with just one arm.
- Enhanced speed: Rocksteady has claimed that his mutation increased his speed and he was able to catch up to Leonard, Michelangelo, and Raphael while they were on a roller coaster.
- Enhanced endurance: Rocksteady has the same level of endurance as a rhino. One such example of this is when he handled being blasted by a Kraang security blaster without showing any indication of being harmed.
- Jagged horn: Rocksteady's mutation caused him to have the jagged horn of a rhino, which he can use for offensively.
- Marksmanship Rocksteady is proficient in using energy blasters despite only having one eye.
Ivan Steranko is known as a passionate collector of legendary historical weapons. Particular highlights of his collection include:
He has been trying to steadily expand his collection - even if the affected object is cursed or in the possessions of his "business partner."
- Kuro Kabuto - Steranko hired Anton Zeck to steal the Shredder's helmet.
- Mystic Dagger - The Purple Dragons wanted to sell him the dagger.
- (To Anton Zeck for failing to get the Kuro Kabuto) "I going to pop your head like blueberry!"
- (Plea to the Shredder) "Let us become reasonable, I'm more useful to you as normal guy, not mutant!"
- "I don't feel so well (notices that he has transformed) Oh Nyet, look at me!
- "Nyet nyet, not so good names"
- (to Anton Zeck) "Hold me close, comrade!"
- "Did no one tell Turtles they is too slow?"
- (in regards to Mikey's insult of his mother) "Hey! Mama does wear the combat boots!"
- "Hey, its not so bad, kinda like the Rocksteady."
- Ivan Steranko went entirely unnamed in his debut episode, with the only indicator about his name being the end credits. Steranko's name was only mentioned in his second appearance.
- Steranko has a hammer and a sickle molded on his knuckle dusters, the hammer and sickle were the symbols of the Soviet Union, and represented the union between workers and peasants.
- He always holds his weapons in the opposite hands: the hammer in the hand with the sickle knuckle duster and the sickle in the hammer knuckle duster.
- Although the computer screen in Stockman-Fly's laboratory showed the silhouette of a white rhinoceros, Rocksteady's nose is shaped like a black rhinoceros since the white rhinoceros does not have a beak-shaped mouth. This could either be an animation error or the DNA placed in the mutagen was a mixture of both rhinoceros species.
- In "Serpent Hunt," it is revealed that he has a brother named Boltak.
- Steranko is the second person to like the name Mikey gives him, the first being Pizza Face.
- Much like his partner in crime, Steranko shares his last name with Jim Steranko, a famous comic book artist.
- While Ivan Steranko is from Russia and Ivan(Иван) is certainly a Russian name, the surname Steranko (Стеранко) is actually Ukrainian in origin. This is not necessarily a mistake, as Ukrainians are the third most numerous ethnicity in Russia (after Russians and Tatars), and Ukrainian surnames are common, though most ethnic Ukrainians in Russia have assimilated to speaking Russian for generations. Jim Steranko, the real person whose name inspired Ivan Steranko's name, is Ukrainian-American.