The woman called Larissa is an enigma. A skilled scientist, medic and warrior who wields Orbital Defender force-field technology powered by her own biology, she prefers to remain secretive about herself, keeping her past hidden from her allies and enemies alike.
Joining Oziron Rael's crew of Micronauts through a quirk of fate, she may not fully trust her new allies, but is dedicated to their mission of saving Microspace from the twin threats of the entropy cloud and Baron Karza. However, she might know more about the latter than she lets on...
The perfect heir
Larissa Karza was the artificially-gestated daughter of Shazraella and Baron Hraal Karza, scientifically created to be the "perfect heir" and artificially grown mentally and physically at over ten times the normal rate, reaching adulthood in only two years. Karza and Shazraella — who rarely visited her when not observing the progress of the accelerated growth procedures — had the scientists that raised her killed, before giving her new living quarters within the secretive complex of her birth, which she was refused the ability to leave.
After finding the prototype Orbital Defender Gear that was developed by her mother, Larissa was able to escape the complex, and — after taking down a group of Lobros muggers in the space of less than a minute — was offered employment and passage off the Throne World by visiting smuggler and businessman Hezlee Ferro. Larissa subsequently spent two years working for Hezlee and Associates as a security agent.
After Saqqura was destroyed by the Entropy Cloud, Larissa was introduced by Ferro to the smuggler Oziron Rael and his crew, whom Ferro had tasked with retrieving medicine from Valtricos research station for him, and had Larissa accompany him on the Heliopolis to protect his interests. Oz, Larissa, the team's Acroyear and Phenolo-Phi warped from the Heliopolis aboard the station, with Larissa criticising the crew's use of mind-affecting warpcore technology; they were quickly found by Valtricos's crew of sentry-bots, which Larissa used her personal force-field technology to defend the team from. Upon discovering that the orbital research station did not carry medical supplies but biological weapons, Larissa — along with her new allies and a Biotron unit — was ejected from the station when a group of pre-conditioned Phobos units attacked them.
As the Micronauts fell to the planet below, Larissa used her force-fields to provide the team cover against the atmosphere and slow their descent. Once they landed, Larissa accompanied Oz, Microtron and Biotron in a supply run to a native settlement; on the way, Larissa persuaded Oz that she hadn't been aware of the station's true nature. When Valtricos automatically deployed a biological weapon onto the planet's surface, Larissa used her force-fields to contain it before Oz sealed it into Biotron's chest compartment, preventing it from harming the natives. When the Micronauts were attacked by an Acroyear II swarm sent by the Ministry of Defense Larissa protected the natives (and Oz) against her attacks, but eventually ran out of power for the shields; however, the team was eventually "saved" by the intervention of Baron Daegon and his Space Gliders. Larissa and the rest of the team were locked in a holding cell on a Ministry of Science ship, where Oz explained his history with the Ministry to them.
When the holding facility was attacked by Ministry of Defense forces aiming to capture Oziron, the Acroyear II warriors identified Larissa as a secondary target, but the ship's shields were restored before they could capture either Micronaut. The team took the opportunity to escape, fighting their way to Biotron and the Heliopolis; once they found Biotron, however, the group was cornered by Acroyear II forces, led by the first-generation Acroyear Commander Raith. The Micronauts fought off the enemy forces, but Oz was stabbed in the chest by Raith, through Biotron's canopy. Through mysterious forces, Oz was restored to life and consciousness, and Biotron — now a conscious, living being that had picked up Oz's thought patterns — led the team to the Heliopolis, which the team used to escape the Ministry of Science ship; when Oz explained his intent to use the ship's warpcore to punch safely through the entropy storm in the hope of saving Microspace, Larissa objected at first, but eventually agreed to his plan.
The dimensional explorer
After flying into the Cloud, the Micronauts were attacked by Reptos, a race of beings previously thought destroyed by the cloud. Larissa fought alongside Oz and Phen until the crew was saved from the Reptos by the mysterious Time Traveler. Several days into their journey, while tracking a mysterious energy source, the Micronauts received a message from Baron Karza. Karza told them that though it had only been a few days for them inside the storm, years had passed for him after he followed them into the cloud. The Micronauts soon arrived at the location of the energy source, or as Karza called it, the birthplace of Microspace: the body of Micronus Prime.
With Karza explaining that Micronus acted as a gateway to another universe which contained a mineral that could prevent the Entropy Cloud's destruction of Microspace, Larissa and the other Micronauts reluctantly agreed to travel through the space bridge, guided by a Time Traveler, who advised them that it was their only hope of saving their universe — even as explosive shards of Ore-13 started to come through the bridge. On emerging from the portal, the Micronauts found themselves in an enormous metal cavern... and confronted by the warrior Snake Eyes, who they mistook for a giant robot in the shape of Baron Karza. The fight between Snake Eyes, the Micronauts, and Arcee was broken up by Soundwave with a sonic pulse, and despite their inability to understand the giants, they managed to come to an accord with Autobot City's defenders.
During the combined Dire Wraith/M.A.S.K. attack on Autobot City, Larissa and the other Micronauts fought back against them, with Larissa using her forcefield technology to attack the Switchblade; however, she and the other fighters were left shocked when Baron Karza, arriving through the spacebridge, Enerchanged with the Dire Wraith army to form a giant body for himself. With the Karza hybrid's energy blasts overwhelming her shields, Larissa retreated back to the Heliopolis. When Oz realised that they could work together with Rom, Soundwave and the humans to Enerchange with the space bridge, Larissa and the others managed to cause it to implode and pull Baron Karza in, despite sacrificing their only way home. In the resulting explosion, the Micronauts were lost and presumed dead by their allies, but were in fact knocked unconscious and captured by human scientists for vivisection.
During vivisection preparations, Larissa was rendered unconscious along with Phen and Oz by an electrical shock. When the conscious Micronauts made their escape, Acroyear carried Larissa, but gave her to Biotron to hold when he moved to fight off pursuing guards. With the help of a sympathetic scientist, the Micronauts reached the Heliopolis and escaped the facility in a human van. While Microtron and Biotron repaired the Heliopolis, Larissa recharged her shields from the human's phone charger before the Micronauts took off through the back doors of the vehicle. As the Micronauts debated their next course of action, Microtron revealed that he had picked up an energy signature matching the Entropy Cloud. Though Oz suggested that the Cloud could act as a bridge back to Microspace, Larissa was incredulous, pointing out that the first time they flew into the Entropy Cloud didn't go great for them.
On flying to the energy source, the Micronauts found a Microspace-scale city populated by insectoid beings, who surrounded them at gunpoint. Larissa readied her shields, but Oz instructed her to back down, wanting to try and talk to them; and, indeed, the team was greeted by the city's leader: a sentient, mobile time chamber. The time chamber led them into a hall filled with records of the death of Microspace — events that had already happened in the future that the time chamber and the Kronus hailed from; as the worried crew ate the food provided and questioned the time chamber, the city was attacked by Commander Klain and his men, who had tracked the Heliopolis there. As to the Micronauts ran to their ship, Larissa suggested that they should preserve the records, prompting Oz to run back towards the hall; Larissa and Phen helped as many of the Kronus as possible onto the Heliopolis, but were left horrified when the beings all crumbled into dust, as the time chamber that preserved their life had been destroyed.
The prodigal daughter
Guided to a Microspace energy anomaly by the helmet that Oz retrieved from the time chamber, the Micronauts were attacked by strange future versions of themselves and their humanoid ship, including a version of Larissa wearing armor based on Baron Karza's. Larissa fought her counterpart, angry that she risked realing the truth of her origins as Karza's daughter, but her future self rebuked her for not telling her allies the truth before. In the aftermath of the fight, the future Micronauts revealed that they had fought their past selves to prevent them making the same mistake they did by returning to Microspace through the anomaly, before fading away. Returning to the ship, Oz noted to Larissa that they had things to talk about, which she agreed with, but asked that they not do so at that moment.
When Oz advocated for the crew ensuring the safety of Rhonda Conway, the scientist who saved their lives, Larissa agreed despite her reservations about how the helmet was "streaming" the relevant information into Oz's head. Arriving at Conway's house, the Micronauts found the building deserted and the family's car missing, but during their sweep they were interrupted by Klain's soldiers breaking into the building. Fortunately for the Micronauts, the humans mistook them for part of Conway's son's toy collection, but only moments later, the soldiers were slaughtered by strange, futuristic Acroyears, who arrived to hunt down the Micronauts. Larissa provided cover with her shields during the fight, and encouraged Acroyear to hurry as they departed, as he was trailing behind to pick up his newest weapon.
With the Heliopolis unable to escape the swarm of strange Acroyears, Larissa defended Microtron and the cockpit with Oz while the other Micronauts defended the engines; overwhelmed by extreme numbers, Oz was forced to activate an EMP, knocking out the attackers and sending the Heliopolis plummeting from the sky, though he was able to reactivate the engines in time. Finding Conway at the home of her stepsister Betty, the crew intervened in time to save her and her family from the revenge-seeking Klain. The Micronauts proposed an alliance with the Conway family, which they accepted.
The Micronauts were tracked down by the Revolutionaries and, following a brief misunderstanding, were shown the enigmatic Talisman — a device that Larissa recognised, though she wasn't sure from where. The Micronauts and Revolutionaries tracked the Talisman to a base on Earth's moon, where — during a fight between their alliance and the forces of Baron Ironblood — Larissa reached the device and found a cockpit within. Enerchanging with the Talisman, Larissa was able to fly it into the air, but doing so triggered an explosive reaction in the Ore-13 that destroyed the base; fortunately, the Micronauts and their allies were able to escape in time. Though Larissa explained to the humans that the Talisman was so complex it would take years to understand it, they fortunately had another source of information on it that they could turn to.
Having launched a global attack on Earth and neutralised its defenders, Membros to take them in. When the Heliopolis was shot down by Membros's Sharkos, Larissa was buried underneath the wreckage, and as such was thought dead by Karza's forces — something that filled the Baron with rage and grief. However, Larissa had survived, and she and Microtron dug themselves out of the wreckage to take the fight back to Karza. With the Time Traveler's helmet offering to guide them to Oziron Rael, Larissa and Microtron — backed up by the Trons, robots built by Microtron, which Larissa was decidedly unimpressed with — made their way to the prison in which their comrades were being held, locating their crewmates' cell within.Baron Karza targeted the Micronauts, sending a crew led by
Confronting Membros within his own torture chamber, the Micronauts were told that Acroyear had been reconditioned into a member of the Ministry of War's armies once more. However, they also discovered the location of the Autobots' prison cell and the Sharkos, which provided them with an escape from the prison. Though the Sharkos was shot down by Raith as they descended to the Ministry's Mobile Operations Base, the Micronauts escaped to confront Karza; the Baron Enerchanged into his centaur form and launched his fist-missile at Oz, but Larissa caught his hand with a force field. Karza, unimpressed, noted that his daughter's heritage would not exempt her, and with an explosion threw her from the base. While the Micronauts called in the Autobots as allies and Karza responded with an Acroyear III swarm, Larissa took down multiple Hornetroids before being retrieved by Phen. Though the fight seemed hopeless with the Autobots overwhelmed, the Micronauts' Acroyear — assigned as the swarm's leader — revealed that the brainwashing had not taken hold, and that he had control over the Acroyear III units. Karza destroyed the swarm with a built-in kill switch, but still seemed to have no cards left to play... until Shazraella, now wielding the power of a Time Traveler, arrived to stand with her husband.
Larissa and the other Micronauts tried to fight back against Shazraella, but her new powers proved too strong, altering time around the Micronauts effortlessly; Oz pleaded with her, claiming she was endangering the universe, but Shazraella reduced him to dust with a wave of her hand. Realising that Shazraella was spreading the power of the Entropy Cloud within the humans' universe, Karza turned on her, but she used her powers to tear him from the body of Micronus Prime, who he was Enerchanged with, and flung him to the ground; Larissa, however, caught her father with a force field, saving his life. The Micronauts seemingly could do nothing against Shazraella until Oz — revived as a Time Traveler himself — appeared, tearing the mad Time Traveler and his powers from Shazraella and imprisoning him within a Time Chamber. In the aftermath, Larissa and the other Micronauts set out on their own, hunting down the Sharkos in the hope of fixing it up.
The Micronauts' captain
With the empowered Oz returning to Microspace to repair the damage of the Entropy Cloud, Larissa stepped up as captain of the Micronauts and their new ship in his place, though Phenolo-Phi found it difficult to follow her in the knowledge that she was Baron Karza's daughter. When the Micronauts were inadvertently "attacked" by a human lawnmower, Larissa rescued Microtron from its blades, disabling it with a force field; moments later, however, a bigger threat came into view as the humans were attacked by Dire Wraith-infected insects, which killed one of the humans in an explosion of Wraith biomatter before attacking the Micronauts. Finding themselves immune to the bugs' corrupting touch, the Micronauts fought them off, though the insects swiftly disintegrated from its own unstable magic. While the crew tracked the insects to their source, Biotron suggested recruiting the Wraiths' archnemesis Rom, but Larissa pointed out that they didn't know how to find him; instead, she ordered that a message be sent to one of Microspace's colonies, so that they could continue the fight if the Micronauts didn't make it back.
Finding the source of the insects, the Micronauts overheard the Dire Wraiths discussing using an airborne pathogen rather than insects to transmit their infection, before being attacked; Larissa, attacked by a once-human Wraith Stalker, put it out of its misery with her force fields. Though they fended off the lower-cast Wraiths, the magic of the Wraith Sorcerers proved harder to deal with, and the crew were forced to flee in their ship. Realising that they would need Rom's help after all, Larissa had Biotron use a record of the Space Knight's energy signature to track him down; however, on finding him, Rom's analyzer falsely marked the Micronauts as Wraiths, prompting him to attack them with his Neutralizer. Rom damaged the Micronauts' ship's thrusters with an energy beam, with Larissa saving it from falling with a force field; however, Rom stood down after Biotron pointed out his own robotic nature, which made it impossible for the Wraiths to truly infect him. After apologising, and purging the false-positive Wraith-matter from the organic Micronauts, Rom flew with them to the sewer base that the Wraiths had been operating from; the Wraiths, however, had already left, leaving only the twisted results of their experiments.
The next day, Rom and the Micronauts managed to track the Wraith D'rge and his acolyte to a fair, where the Wraiths were releasing their toxin. Biotron was able to contain the pathogen within his cockpit, but the virus congealed itself into a blob of living Wraith-matter and broke free, attacking the Micronauts while D'rge ensnared Rom. Realising that their weapons were having no effect, Larissa directed Rom to use his Neutralizer on the virus, containing the blast and shielding her allies from its effect with her force field. Angered, D'rge blasted the Micronauts, but was shocked to find that they had shielded themselves from his magic — and that Biotron had used his technology to devise a cure for the virus, leading the Wraith to escape in a swirl of light. The Micronauts and Rom subsequently parted ways, secure in the knowledge that they had found new allies. At some point after this, Larissa shaved her head bald.
Not long after their encounter with the Wraiths, the Micronauts tracked Baron Karza to a lighthouse, where they realised that he had been working together with the Dire Wraiths. Deciding to turn to Rom again for help, the crew found him and his allies having purged a Wraith cell in Utah; Rom agreed that their aid would be needed, though Larissa was apprehensive about working with the Wraith-altered Camilla Byers. Together, they stormed the Wraiths' base in Yucca Mountain construction site, but when Rom engaged Baron Karza, Larissa was shocked to see her father Enerchanging with Rom, and draining the Space Knight's power to increase his own size and strength. Despite trying to stop the Wraith Sorcerer whose magic was allowing this one-way transfer of power, and Larissa reaching out for their ally, the Micronauts were caught in an explosion caused by the Baron and left unable to stop Karza from completing the transfer and banishing Rom from existence. Though Rom's allies could find no sign of the Micronauts or Rom himself, they were not dead, only buried beneath rubble — and the Micronauts' scanners informed them that Rom was not dead either, having been bridged to Microspace.
Locating Rom in their home dimension, the Micronauts found him under attack by Dire Wraith-infected Reptos, and forced them into retreat; though Acroyear forced to pursue, Larissa had him stay and get Rom to their ship's rejuvenator. As they caught each other up on their mutual foes, Rom and the Micronauts came to realise that Karza and the Wraiths intended to use the time-warping qualities of the Entropy Cloud to advance the awakening of the Wraiths' dark god, the Presence. As they sought out the Wraiths' Stronghold to stop their scheme from reaching completion, Larissa took it upon herself to instruct Rom on the methods of Enerchanging, demonstrating by momentarily taking on a centaur form. As she taught him the finer points of forcing Enerchange with another, Rom asked why she refrained from using her centaur form in battle; Larissa confessed that its resemblance to her father's own Enerchanged form made her reluctant, fearful as she was of becoming more like him.
As they approached the Stronghold, the Micronauts were attacked by a Wraith-infected Hornetroid, which caught Acroyear in its pincers before he was able to kill it; however, the infection was transferred to Acroyear, who turned on his allies.Larissa's force fields were only able to hold the super-soldier momentarily before he broke free, but Acroyear's consciousness managed to force the Wraith to a standstill long enough for Rom to burn the infection out. Realising that the Wraiths would soon detect them no matter what they did, Larissa had them carry out a direct frontal assault, using the corpse of the Hornetroid to disguise themselves until they got close enough and ramming through the fortress's shields with their ship; with the Micronauts keeping their enemies' defenders busy, Rom destroyed the Wraith-matter that was allowing the Entropy Cloud's power to be channelled to Earth. However, Larissa realised that Karza and the Wraiths would likely have a backup plan, and headed for a spacebridge to return to Earth.
Rom and the Micronauts returned to Earth in time to rescue Camilla, Darby Mason, Livia and Orphion from an attack by Wraith ally Axiom. The Wraiths fleeing, Livia explained that Karza and the Wraiths had gathered on Japan's Hashima Island, manipulating the governments to prevent them from gaining reinforcements. Larissa, counting on her father's arrogance, advocated that the "giants" draw the enemy forces while the Micronauts used their size as an advantage, getting Rom close to Karza. As they headed for Karza's base within a former coal mine, the Micronauts were attacked by Axiom once more, but Rom was able to steal his energy and size much as Karza had his own — though the fact that the energy was not his own made for a death sentence if he kept it too long. With Rom back at his full size, Larissa and the Micronauts headed for their foe, only to find that they were too late: the summoning of the Presence had already begun.
- Larissa's profile on the title page of each issue of Micronauts claims that she created the Orbital Defender gear herself, but this was contradicted by her Hasbro Heroes Sourcebook profile, which established that it was designed by Shazraella.
- Larissa's status as the daughter of Baron Karza and a member of the Micronauts is remeniscent of Persephone, a character from Image Comics' Micronauts revival.