Legacy of the Creators

Aptom was initially developed by the scientists at Chronos to be able to defeat their enemies by creating new class of Zoanoid who could change it's form at will and adapt it's body with powers and abilities specially designed to defeat an enemy's own special powers. Unfortunately this experiment was not a success, the resulting failure being the Lost Number known as Aptom. Eventually after being reprocessed by Dr. Barcus Aptom did develop the ability to mimic other Zoanoid's powers (and in many cases improve upon them) but he also had is own thirst for power enhanced as well. By gaining the ability to absorb other Zoanoids Aptom's own will to rule the world made him an enemy of his own creators, to the point were Chronos had to actually start developing abilities and countermeasures to block the very creature they had developed. One additional feature, that again Chronos must dislike greatly, is that if injured Aptom has the ability to regenerate from any injury even if only a small part of his body still exists. By absorbing any Zoanoid body Aptom is able to rebuild his own form using the captured creatures own tissue.

Though out the series, after he was branded a traitor by Chronos, Aptom has sided with Sho and company in order to take down Chronos. But all the while he was helping to keep Sho and his friends alive Aptom is also biding his own time for the chance to finally take his revenge against Sho for the "murders" of Somlum and Dyme.

During the course of the series Aptom developed numerous battle forms, some intentional, others not so much:

Type 1
This is Aptom first form during his first encounter with the Guyver. Hoping to be able to copy the powers of the Guyver he morphed his body into a similar looking creature but the weaponry of the true Guyver was no match for his imitations. Aptom was easily defeated by Sho.

Type 2
Following some experimentation and reprocessing by Barcus Aptom truly gained the abilities he was designed for. He was able to absorb and combine the battleforms of a Gregole, Vamore and Enzyme II units into a hugely powerful Zoanoid. This form had the strength of Gregole, the bio-blasters of Vamore and Enzyme II's corrosive compound.

Type 3
After being defeated by Sho but surviving due to his regenerative powers Aptom set his sights on those Zoanoids who were the elite and most powerful, the four remaining Hyper Zoanoid Team Five members. Infiltrating Relic's Point Aptom quickly absorbed Elegen, Gaster and Derzerb. This form featured Derzerb's strength as it's base, Elegen's electric powers and Gaster's bio-missiles.

Type 4
Being a creature who always wanted to improve himself Aptom then set his sights on the last of the Hyper Zoanoid Team Five, it's leader and most powerful Zoanoid warrior, ZX-Tole. Eventually he achieved his goal and absorbed ZX-Tole adding to the power of "Form 3" ZX-Tole's flight and bio-blasters. But ZX-Tole was able to escape from Aptom's absorption attempt though to fight to avenge his former team in a new form.

Chaos Form
After being branded a traitor by Chronos one of the group of Rogue Zoalords thought they could use Aptom to increase their own power base. By modifying a Gastal unit with a special virus the rogue Cabraal Khan was able to take control of Aptom's multi-zoanoid form but the resulting creature was mismatched and chaotic due to Khan not fully understanding Aptom's unique biology.

Evil Form
Eventually Khan was able to understand Aptom's physiology and the resulting new form that was created through his total control of Aptom was more powerful than ever before. But unfortunately also somewhat random due to various Zoanoid battleforms that were used to create his own battleform. Eventually through the help of Sho and Bio-Freezer Aptom was finally able to escape from Khan's control.

OmegaBlast Form
Aptom's most recent battleform. This form appears to be a mixture of his "Form IV" along with Bio-Freezer and several other units. This form features a combination of abilities including Bio-Freezer's temperature control, Gastal's stealth ability, Zanngallo's molecular accelerator and a high frequency sword.

More recently it have been revealed that Aptom can combine with other units to create a "hybrid" unit, as seen by absorbing Guyver I to sneak into a Chronos HQ.