Osmosian

Osmosians are a human subspecies.

According to Proctor Servantis, Osmosians are just humans with a unique genetic component that gives them powers.

Appearance
Osmosians are outwardly indistinguishable from Humans except for the fact that Osmosians live for hundreds of years, and that they begin to grow four small, rounded, flesh-colored horns on their forehead as they mature, at about 100 years or so of age.

When an Osmosian has recently absorbed energy, they develop black marks around their eyes.

Reproduction
Osmosians can reproduce with humans due to their close relation.

Mutations leave a genetic imprint on the Osmosian's DNA, so when an Osmosian has had a mutation and breeds, the mutation can be passed down to the offspring. Seen only with Devlin, in this case, it seems the offspring won't always inherit the ability to absorb, although, this might instead be because Devlin was part human. The offspring will be able to shift from their normal form to the mutation and back at will, will keep their sanity and it appears that their powers and ability are not limited to 1/10.

Diet
Osmosians normally eat food to sustain themselves, they can also feed off of the metabolism and life force of other living beings. However, this method of feeding can easily turn into an addiction (as energy is also like an addictive drug for Osmosians), causing the Osmosian to become insatiable and instinctively seek out any possible source of energy to feed off of.

According to Matt Wayne, Osmosians prefer savories to sweets.

Powers and Abilities
Osmosians have different abilities depending on the individual like certain Osmosians having the ability to absorb matter and energy from nearly anything and use it in various ways.

Energy Absorption
Osmosians can channel absorbed energy through their hands to manipulate technology, discharge it as an energy blast, or use it to speed up cellular regeneration.

Osmosians can use absorbed energy to increase their strength or recover from injuries at an accelerated rate.

Osmosians can train to use their powers more efficiently, so that they can control the amount of energy they absorb, the rate of absorption, and how they control and discharge it better (though the action is still risky, and can cause side effects).

Matter Absorption
Osmosians are able to absorb and synthesize the mass, properties, and chemical makeup of matter to change their body into living matter in the shape of the Osmosian, the absorbed matter is as durable as the matter used to make it and can enhance their strength and durability.

Osmosians can also extend absorbed matter to anything they are touching.

Osmosians can repair objects composed of the same matter they have absorbed by synthesizing a liquid version of that substance and hardening it again.

Osmosians can manipulate whatever substance they are touching by absorbing it and morphing it into any shape or form.

After absorbing matter, Osmosians can manipulate their atomic structure to grow extensions on their body and shapeshift their limbs into various weapons, tools, and forms at will.

Power Absorption
When Osmosians absorb the energy and DNA of other life forms, they gain that creature's powers and abilities, but only at 1/10 of their strength. Their bodies will undergo a slight mutation (or none at all, depending on the powers they have absorbed) to accommodate the absorbed abilities; for example, when Aggregor absorbed the powers of a Geochelone Aerio, his appearance remained unchanged, but he could open six holes on his torso to blow air out of.

The amount of energy an Osmosian can absorb at once, as well as the extremeness of the mutation, depends on their experience.

If an Osmosian were to absorb DNA of several life forms at once or from the Omnitrix or Ultimatrix, the absorbed DNA will overwrite their own, causing them to mutate into a fusion of the absorbed aliens. While they can be powerful with these mutations, their powers are still just 1/10 of their original strength. However, because they are a mixture of aliens, they can mix and match their abilities. In addition, their mutations can limit their ability to utilize the special powers of the aliens they have absorbed; being a random fusion of aliens, they can only access the powers that make up the major components of their mutant form unless the power does not require a very specific organ or appendage.

Sometimes, when an Osmosian absorbs feedback from the Omnitrix, the Osmosian gains the ability to turn into each alien currently unlocked on the Omnitrix at will, but can only turn into themselves for a short time, but can sometimes revert to normal without meaning to. They will also be able to mix and match body parts, for example, one alien's body with another alien's head. If the Osmosian loses control over the energy absorbed in the feedback, they will turn into a mutation of the aliens they could use. This all happened to Kevin in Framed.

When an Osmosian takes on a mutation, they can learn to shift between their normal form and mutation once enough time has passed. According to Dwayne, Kevin managed to revert from Kevin 11 once, explaining why he was wearing jeans instead of cargo shorts, before becoming stuck as Kevin 11 again due to lack of experience.

Other Powers and Abilities
Even without absorbing energy or matter, Osmosians possess a minor degree of enhanced strength and durability. This has been demonstrated by Kevin, who, even without absorbing matter, is strong enough to lift and throw an unusual amount of weight and resist physical damage that would normally severely injure an average human. According to Dwayne, an Osmosian's enhanced strength and durability does not come from the energy and matter they absorb; rather they possess enhanced strength and durability naturally that is simply increased when they absorb matter or energy.

According to Proctor Servantis each Osmosian have their own abillities. He also gave an example: Kevin's abillities are specially related to energy/matter absorption.

Weaknesses
While Osmosians are stronger and more durable than an average human, they are largely powerless without matter or energy to absorb.

Absorbed energy will be used up over time or through excessive use, so Osmosians using energy will be required to recharge.

Osmosians must have a decent amount of matter to completely encase themselves into.

An Osmosian's biggest weakness is their insatiable hunger for energy and becoming mentally unstable, though this is only a problem if they absorb energy and become this way; this trait is normally latent and becomes easier to control if they are mature and have experience with absorbing energy. Storing energy for long periods of time will worsen their instability.

If an Osmosian is forcibly drained of the energy they have absorbed, it will restore their sanity but also present risks to their physical health if they do not have medical attention as the process will either leave them exhausted, famished or weakened to the point of unconsciousness due to them having been living off energy instead of eating and sleeping properly.

Any powers an Osmosian has absorbed from other life forms will eventually wear off and disappear. The more life force, metabolic energy, and DNA they absorb, the longer it takes for their absorbed powers to wear off.

Regardless of how much DNA an Osmosian absorbs, their own DNA will eventually overwrite the absorbed DNA in time, causing them to lose absorbed powers, unless they keep reabsorbing to keep it from happening.

Notable Osmosians

 * Aggregor

Main Timeline

 * Kevin Levin (1/2 Human)
 * Kevin 11 (1/12 Osmosian)
 * Ultimate Aggregor (1/6 Osmosian)
 * Ultimate Kevin (part Osmosian)

Ben 10,000 Timeline

 * Kevin Levin (part Osmosian)
 * Devlin Levin (1/4 Osmosian, 3/4 Human)

Etymology
The name Osmosian was created by Proctor Servantis. It comes from the word "osmosis", the process by which a solvent (e.g. water) diffuses from an area of a high concentration through a semi-permeable membrane into an area of low concentration.

Trivia

 * According to Dwayne McDuffie:
 * Osmosian DNA is in the Codon Stream.
 * Osmosians growing horns as they mature is something they thought of after Paradox aired.
 * Osmosians' powers are similar to that of Absorbing Man from Marvel Comics. Like them, Absorbing Man could absorb the properties of any solid substance, could turn his clothes into the substance and turn his hands into melee weapons. However, Absorbing Man couldn't absorb energy.