Aptom in canon
His first appearance in the OAV - as in the manga before it, and the TV series after - took place alongside his two comrades and fellow Lost Numbers: Somlum and Dyme. Aptom was very fond of Somlum and Dyme, having bonded with them over the shared hardship of their lives as Lost Numbers. They were seemingly his only two friends; Zoanoids seemed to be fairly indifferent to him, and Hyper Zoanoids held him and his kind in contempt, mocking them behind their backs.
And, likely to their faces, as well.
Needless to say, this has inspired a great deal of bitterness on Aptom's part toward his "employers". Despite the fact that he is one of the Zoanoids created by Chronos, he feels no affection for the company. Only the fact that his friends worked for the company seemed in any way capable of keeping him there.
However, the fact that they were placed on the front-lines of Chronos' battle against Guyver I, meant that they would eventually find themselves in a life-threatening situation.
Such as the one that they were placed in on the night that Chronos decided to kidnap Sho's father, and take him into their custody as part of a two-pronged effort to break Guyver I's will to resist. This plan, however, only succeeded in riling the boy up. After killing Somlum and Dyme, right in front of their wounded comrade Aptom, it was revealed to the boy that his friends had been in danger, as well as his father being spirited away while he was fighting Aptom and his two cohorts, succeeded in accomplishing the aims that Chronos had sought.
Luckily for Sho, however, a mysterious man with a large gun had been tracking him since before the fight began. With his help, Sho was able to escape. Aptom, missing an arm and ordered to retreat by Richard Guyot, made a vow of personal vengeance on the Guyver I that night.
From then on, whatever it took, he would kill Guyver I.
However, with the injuries he had sustained, Aptom was forced to undergo reprocessing at the hands of Dr. Balkus; something that the old Zoalord would come to regret a great deal in the future. As his body was regenerated by the processing fluid, and his physiology was altered by Balkus to serve a new purpose, Aptom had ample time to reflect on his bitterness for Sho, and to stew over what the boy had done to his two comrades. All of this served to make him one of Sho's most relentless foes.
Once he had been released, his powers improved and with a few additional surprises provided by Dr. Balkus himself, Aptom wasted no time in hunting down Sho once again.
Sent to spy on the actions of Richard Guyot, Aptom caught up with Sho just after he had been put through one of the worst experiences of his young life. Aptom was quick to capitalize on the psychological trauma that he knew the boy would be suffering after such an event. Not wanting to kill the boy at his weakest, feeling that the memory of his comrades wouldn't be avenged properly if he did so, Aptom instead goaded to boy into overcoming the mental block that he had formed against summoning the Guyver, by the simple expedient of threatening to kill Mizuki if he didn't transform.
As planned, this lead to Sho's regaining the resolve to transform into the Guyver and fight. Contrary to what Aptom likely intended, however, Sho turned his Mega-Smasher on the rogue Lost Number, obliterating most of his body and reducing him to a single, severed lower-arm. This was seemingly the end of Aptom, and the Lost Number Commandos with him.
However, that was not to be.
With his regenerative powers enhanced to levels heretofore-unseen in a Lost Number, Aptom was able to reconstitute his head, upper-torso, and left shoulder, thus surviving an attack that had killed several Zoanoids - and a fair few Hypers - before him. He would have been left to his own devices, to find some way of dragging himself back to Chronos to get treatment for his wounds, if not for the timely arrival of Team Five, who had been drawn by the Mega-Smasher's light and that of Aptom's own bio-lasers. Hiding himself in a tree, Aptom pounced on the form nearest to him: Elegen.
Clinging to the eel-like Hyper Zoanoid's back, Aptom did something that he had never done before: he began to absorb a living Hyper Zoanoid. This action brought him to the direct attention of Dr. Balkus for the third time since he had been sent out from Relic's Point after Guyver I. This time, he wouldn't be going back; Aptom had had it with being treated like a disposable lab animal at best, and while he was absorbing Elegen, he made it clear to Balkus just what he intended to do.
Taunting the old Zoalord with his newfound powers and independence, Aptom even challenged the remaining members of Team Five themselves. Thanks to the powers that he had added to his already-considerable arsenal, Aptom was able to beat off - but not permanently defeat - the four remaining members of Team Five. He then left, with a final warning that he would return, and that Gaster would be his next target when he fed.
Disappearing into the forest, leaving only his taunting laughter behind, Aptom set out to seemingly test the limits of his newfound independence.
Eating any and all Zoanoids that he came across - including several groups that had been sent out for the sole purpose of hunting him down - Aptom swiftly gained Dr. Balkus' complete antipathy.
Taking a few moments to consider his next course of action, Aptom decided that - since ordinary Zoanoids weren't giving him new powers or any more strength than what he had previously gained, and since the remainder of Team Five hadn't shown up no matter what he'd been doing - he was going to try for something more powerful: a Zoalord; Richard Guyot. As he made his way back toward Chronos' base at Mt. Minakami, leaping through the trees as opposed to making his way through the forest on foot, he was halted in his progress by a sudden flash of bright light.
The figure hidden behind all the light had a strong - nigh overpowering - aura of authority. Something that even Aptom was able to recognize, though as a Lost Number it didn't affect him nearly as badly as it did the five Zoanoids that had also encountered the newcomer. Sensing that this new apparition possessed great powers, Aptom was determined to claim those powers for his own.
To that end, he made a hasty - and ultimately foolish - attack on the newcomer.
He was handled rather quickly by the newcomer; unknown to him another Zoalord named Alkanphel. Despite the fact that he was uneasy about attacking, due to the forceful presence that all Zoalords have to any Zoaform of lesser stature, Aptom was still able to move forward with his attack. Quite unlike the five Zoanoids, who by that point had already been killed.
Left in three pieces by Alkanphel's energy blast: his head, right arm, and the remainder of his body, Aptom was forced to make use of the Zoanoid corpses scattered around him. This would be his first time creating clones of himself, but not the last.
Unwilling to forgive Alkanphel for nearly killing him, Aptom headed for the last place that he had seen the Zoalord going when he had thought himself through with Aptom: into Mt. Minakami. making his way past the guards, likely with both the aid of his disguises and his "fusion predation" ability, Aptom was able to settle himsel(ves) into one of the control rooms for Relics point. The very one that, as it happened, the three remaining members of Team Five were ensconced.
Given Aptom's tenacious nature, and his dedication to his promises, it is not likely that this was simple happenstance.
Waiting until the opportune moment, taking advantage of the chaos consuming Relics Point, Aptom made his second strike against the remaining members of Team five by eating Gaster alive, presumably while the other struggled but was unable - for whatever reason - to escape. With the help of one of the other clones he had created after his close encounter with Alkanphel, Aptom was able to ambush Derzerb and Zx-tole, and would have succeeded in his plan to absorb the former, had it not been for a quick warning from the latter. His clothes seared off by the heat of Derzerb's transformation, Aptom landed on the floor, naked and somewhat worse for wear.
It would not be the last time such a thing happened.
Facing the transformed Derzerb, and the furious Zx-tole who was not long about transforming himself, Aptom was quickly disposed of by a barrage from the latter's bio-lasers. However, that had been accounted for, and Aptom had ensured that he would have several chances to attack and absorb the remaining members of Team Five; he still had two other clones waiting in the wings. The second clone, wearing the form of Gaster, deceived Derzerb - and even Zx-tole himself, for a short time - into thinking that he was their ally. Once he grabbed for Derzerb's arms, he revealed himself to Zx-tole; but by then it was already too late.
With his infectious cells already invading Derzerb's bloodstream, even Zx-tole blasting Gaster's body out of existence with his full complement of bio-lasers wasn't enough to stop him; nor to save Derzerb from what happened next. Aptom, using the genetic information that he had collected from the other two members of Team Five, combined Derzerb's base form with Gaster's bio-missile launchers and liquid-explosive discharges, and Elegen's electrical-whip tentacles and electricity manipulation abilities. This was the second such combined form he had adopted, and his third form overall.
Taunting Zx-tole, Aptom revealed that the creature he had fought was indeed the real Aptom, but that it had been merely one member of the group cloned bodies that Aptom had under his control. He did not, however, reveal just how many bodies he had cloned in such a fashion. Telling Zx-tole flat-out that he would absorb him next, Aptom launched a frontal assault on the sole remaining member of Team Five.
Zx-tole himself was only barely equal to the challenge; Aptom's combined form possessing far greater speed and agility than his bulk would have suggested at first. Wounding Team Five's leader with the liquid explosive he had obtained from Gaster, Aptom managed to disable his forehead-mounted bio-laser. Then, with the aid of a barrage of biological missiles, Aptom knocked Zx-tole down several levels, leaving him lying in a crater on the uppermost level of Relics Point's central shaft.
However, just as it appeared that Zx-tole had been beaten at last, he revealed the final weapon that he had kept in reserve. At first, Aptom was dismissive of this latest and last gambit, seeing it as nothing more than the Hyper Zoanoid being able to create cold air in an attempt to slow him down. However, nothing could have been farther from the truth; so Aptom realized when the heat and light that Zx-tole had absorbed with his wings came blasting back out at him, converted into the energy for Zx-tole's Blaster Tempest.
The energy unleashed by the Blaster Tempest left Aptom with three-quarters of his body gone, clinging with tenacious strength to a crumpled scrap of reinforced concrete. When he climbed back up, hampered as he was by the loss of his left arm and so much of his own biomass, it was to find himself confronted by Zx-tole. Thinking Aptom defeated, Zx-tole began preparing to fire his wrist-mounted bio-lasers.
However, Aptom had been prepared for even this, and had his third and final replicant-body lying in wait under the floor. As the last of Aptom's clones latched onto him, driving assimilation tendrils into his left leg and preparing to infect his entire body from there, Zx-tole severed the afflicted appendage and burrowed into the floor to escape. Aptom was supremely unconcerned with this, since he still held the severed limb and with it all the genetic sampling he would need.
Combining the forms of all four members that he had managed to absorb from Team Five, though Zx-Tole's characteristics were predominant, Aptom found his attention drawn to the lowest level of Relics Point; and the clash of great and terrible powers that was beginning there.
Even as Aptom watched, unable or unwilling to leave, the Relic that Relics Point had been named in honor of was activated. Rising to the surface, powered upward by the massive energies that it it had absorbed from the magma chamber beneath Mt. Minakami itself, the Relic was also equipped with a shield made of energy-waves so powerful that they were nearly solid. Aptom found this out the hard way, as he was knocked from his perch in the rafters following the Relic's appearance beneath him.
Leaving Relics Point behind, Aptom made his way back to the surface and escaped from Chronos' sphere of influence through some still-unspecified means.
Settling himself in Shinjuku, where Natsuki had been hiding the survivors of the Mt. Minakami debacle, Aptom made it his business to protect them from Chronos; at least until he could have his long-awaited reckoning with Guyver I. Knowing from close, personal experience just how hard any Guyver was to kill - and likely also considering how tenacious Sho was even beyond that - Aptom was certain that he and Guyver I would have the chance to meet once more.
Making his way into a deserted section of Tokyo, Aptom leaped the fence on a construction site and turned to confront the man he'd heard - or perhaps just sensed - following him. Said man turned out to be Zx-Tole, reprocessed into a new and better version of himself - equipped with antibodies specifically designed to repel Aptom's invading cells, and a virus to disrupt his healing abilities - though he'd been rendered a Lost Number by the procedure. Unaware of what he would be facing, Aptom was quick to offer a taunting challenge.
However, he quickly found himself outmatched by Zx-Tole's newly-enhanced battleform. Called Neo Zx-Tole now, though Aptom wasn't to know that, the former Hyper Zoanoid - now a Lost Number, just as Aptom himself was - was easily able to force Aptom to heel.
His mauled battleform landing in a heap before the very people who he'd been trying so hard to protect in secret, Aptom was hardly pleased to find them all arrayed around him, gawking. Before he could berate them too long for their grievous - at least in his eyes - idiocy, the Zoanoid he'd been fighting - Neo Zx-tole - landed before them all. He was rather surprised to find most of the people that he'd once hunted on the orders of Dr. Balkus gathered in front of him; still, dealing with Aptom was his primary focus.
Aptom, however, was granted a reprieve by one of the last people that he likely expected to do so: Guyver III.
However, even he wasn't able to make a dent in Neo Zx-tole, leaving Aptom and the others to the whim of the merciless Lost Number. Before anything else could happen to them, Mizuki's distress awakened Guyver I from its year-long hibernation. Emerging with a new and more powerful armor, the Guyver - Sho himself was still unconscious inside the armor, as he had been when the armor itself first activated - obliterated Neo Zx-tole, leaving Aptom free to make his escape with the help of a spying Rocies; leaving only the promise that he and Sho would meet again.
Later, when the Zoalord Imakarum Mirabilis was attacking Sho, Aptom did indeed return to intervene in the battle: pulling the wounded Guyver out of the way of a barrage of bio-laser blasts.
Forced to retreat in the face of Imakarum's overwhelming power - power that reminded him of someone he had faced before - Aptom quickly found himself deprived of half of his right leg and left wing. A missile barrage served as sufficient cover for Guyver III to ambush the Zoalord, but his strike proved ineffective. This prompted Imakarum to transform.
Aptom in Warrior Guyver
Aptom in Son of Mine ('verse)
As in canon, Aptom was one of three Lost Numbers that were sent out to deal with Guyver I, and then came after him for revenge once his comrades had been killed.
Aptom still harbors a desire to settle with Sho in the most final way possible, but the bonds that he has formed with the two Lost Units that were staying with Sho's other friends have made him a bit calmer and more thoughtful. Though no less determined to carry through with his vengeance.
Later, though, once Sho had reemerged from the Relic-created cocoon that he'd been regenerating in since the eruption of Mt. Minakami, Aptom was both eager and quick to get back to his original goals. When Ryan Crouger, who had gone off on his own after an argument with Agito, appeared before him, Aptom decided to pursue an angle that would have - had it worked - granted him a substantial advantage over Sho.
Aptom tried to consume a Guyver.
However, the Guyver that he attempted to consume - Ryan Crouger - was not one to give up without a fight. Normally, such a thing wouldn't have mattered in the slightest, but the fact that one of the Hyper Zoanoids - Elegen, the user of bio-electricity - had not yet been fully subsumed by Aptom's digestive processes gave this tenacity more weight than it would have otherwise had. Through an as-yet unknown set of circumstances, Ryan's body fused with the remains of Elegen's, granting the Fifth Guyver a set of Hyper Zoanoid-like abilities.
Needless to say, Aptom wasn't pleased with that development.
His further attempts to consume the hybrid that had resulted from Elegen and Ryan's mergance all ended in the same failure as his first, though often not in the same way. Finally, after the two of them met once again in L.A., Aptom had resigned himself to leaving the hybridized Guyver alone. For the most part, anyway.
Aptom and Ryan have a somewhat adversarial relationship, though this mostly extends to ribbing and gently - though sometimes not-so-gently - mocking and insulting the other.
He isn't particularly sure what to make of Sean, though the other Guyver's complete lack of respect for the kind of things that Chronos is capable of annoys him in the extreme, making him more inclined to abuse the Fourth Guyver either verbally, or - on rare occasions - physically.
He finds the soldiers working with the Fourth Guyver to be an interesting bunch, and not nearly as stupid as he thought, judging by the Guyver they were sheltering. It lead, in the end, to him developing something of a respect for them, and deciding that he would leave a small number of his "clones" behind while he himself returned to Japan.
Aptom's main interest, however, lies with the young Zoalord Ingriam. He has tried several times to consume the young Zoalord, and thus add the boy's powers and considerable reserves of bio-energy to his own. Every attempt thus far has ended in failure; most due to the intervention of the boy's father, but his attempt in Los Angeles was thwarted by a small squad of Enzyme IIIs that Ingriam was commanding at the time.
When he reached Japan again, and having broken off from Ryan once he was sure that the Guyver would be able to get himself back to his fellow Guyvers without any trouble, Aptom left them to go feed, promising himself that he would come back soon.