Nicknames:

Triality
Forbidden Conduit of Triality
Tertius
Combo of Nexus, Cosmic Essence, and Detetmination

Date to Birth: Unknown

Place of Birth: Unknown

Species: Forbidden Conduit
Gender: Genderfluid (Can be both)
Height: Unknown
Weight: Unknown
Hair Color: All Colors
Eye Color: Purple

All 3 of the most powerful sources, coursing through me, I am a perfect combination.-Tertius.

The Forbidden Conduit of Triality, Tertius, is an extremely powerful Forbidden Conduit, and is one of the most dangerous and strongest ones to ever exist in all of time, due to the fact that his parents of Forbidden Conduits that control the Nexus and the Cosmic Essence, with a vessel of one of his parents being able to manipulate DT to the fullest level.

Backstory:

In the world of the Conduits, there are 2 extremely powerful Conduirs that exists, the both of them are of the Forbidden Class, Time and Space and Networks.

The forbidden conduit of Time and Space is said to have been the result of the Cosmic Essence getting too close to the Cycle and supposedly created a accidental deity that not only was documented being the strongest of the forbidden conduits, but still holds that title. The forbidden conduit existed for only one cycle,but was said to be without form and only voice, it would name off the names of every being in existence and would ever exist. It didn't stop there, the forbidden conduit also reformed the entirety of the Eden Tree along with all the orbs of the Tree into what looked to be a giant spiral where it then proceeded to make what it called "The Absolute".

The Conduit of Networks also known as "Nicole" was created when Knowledge tried to create another entity; that possessed his knowledge. However when Nicole gained a mind and removed the flaws of human emotion and empathic emotions they became a threat to all known systems. Computer systems and even fragments Cyberspace. Eventually Nicole would become part of the inner workings of all numerical functions, geometric spaces/systems and even al softwares. Nicole would become a all-powerful being within the Nexus. Hidden themselves within the depths of all codded fragments a part of Eden and beyond, not even the Nexus is able to find and delete her. Eventually a new realm would be created within the coded islands called the "Cybertopia," by the hands of the Forbidden Conduit.

Both Conduits that utilize the Nexus and Cosmic Essence have never met before during this one cycle, but Nicole, has heard of Time and Space, due to the Nexus having a sort of file on them. And because of this, Nicole became interested in the Conduit of Time and Space, for it is like Nicole, only that he is able to possess the Cosmic Essence, which is the opposite to the Nexus that Nicole utilizes. Because of this, Nicole desires to meet with the Conduit of Time and Space. But she'll need to find him somehow, for he is a sort of being that lacks a form of his own, as well as being only a voice. But thankfully, he can also take on the forms of other beings, which is why she needs to find a way to gain his attention. All the she needs to do it to find him.

Nicole then went into the outside realm, and goes to try and search for him, which was not an easy task, due to the fact that she has no idea where he is. After all, she is also a being without form of her own. But as she looks around in order to try and find him, she is able to see a change in what she would see as a giant tree. Thinking that it is him, she calls out to the Conduit of Time and Space. And luckily for her, the call was answered, and the tree wasn't being altered. The Conduit of Time and Space was surprised to hear the voice of a Conduit that he did not know of, and he went to see who it is, only to sense that it is a Conduit that is strong of her own right, and controls the Nexus, which he did not expect to see nor think of as being possible.

The 2 Conduits talked to one another, both about their origins and their purposes, and needless to say, both are very impressed with one another, due to the fact that the both of them are likely as strong as one another, but in different ways, and both have even made realms with the sources of power that they had used. They are rather interested in one another, due to the their similarities, even if there are differences in their experiences as Conduits, and because of this, both want to show the other of what they are able to do. And so they did, they are able to show one another of their capabilities, and are even able to make objects together, possessing both Cosmic Essence and Nexus together, which is something that is mainly in the AUs and ATs, and even different Multiverses, with the Nexus being present at the Eden Tree, and needless to say, the creation challenge that both Forbidden Conduits do is a rather exciting thing. And because of this, they want to take it a step up and further their creations in the biggest way possible, even making a location of both Nexus and Cosmic Essence which the both of them named the Fields of Duality, where Nexus and Cosmic Essence intertwine. And it is one of their greatest creations to ever exist. But Nicole...she wanted to take it further, much more further then expected. And because of this, she asks the Forbidden Conduit of Time and Space to make a child with her, in order to see how strong the child is. Although, Time and Space was admittedly reluctant, as she has no idea how strong the child is, and the fact that it would require a lot of power, he agrees...but then remembers that there is another source of power that they can use in the creation of the child, which is that of Determination. And there was a perfect host to make it happen.

The Conduit of Time and Space searched everywhere to find the perfect host he wants, even going to other Eden Orbs and even to a point in the future of said Eden Orbs, and eventually, he found it, it was none other then 100 himself. In the way that he sees it, 100 is the strongest user of DT in all of existence, due to the fact that he is able to empower himself with rage, and the fact that his DT also grows strong. He is likely at the level of MAX or MAX+. And that is perfect enough for him to use 100 as a vessel for the mating ritual in order to make the next Forbidden Conduit. Taking over 100 during a very strong peak, which allows him to rival the Forbidden Conduits, he and Nicole began to utilize their mating ritual. It was difficult, as 100 was starting to fight off the possession, and his rage is getting stronger by the passing minute, but eventually, the mating was a success, and the Conduit of Time and Space sent 100 elsewhere before he can cause damage. And after that, it is time to play the waiting game, the hardest game to play, which even the Conduits do not like, and the other normal Conduits, they would most likely go and find Nicole, find out about the new Forbidden Conduit about to be born, and would try to kill them.

But luckily, Nicole is inside of Cybertopia, as she and Time and Space were inside of it. And the baby, they can feel it inside of Nicole, having Nexus, Cosmic Essence, and Determination by an equal amount of 1/3 for each, creating an exceptionally strong Conduit, one far greater then even both of the parents themselves. And eventually, after what must have been a long time, the Forbidden Conduit of Triality was born, and is given the name, Tertius.

The moment that the child was born, there became a change in the entirety of Eden Tree, as a burst from them, and the Conduits realize that there is a new Forbidden Conduit, but they have no idea who it is and where, as the Forbidden Conduits of Space and Time and Networks stay the Fields of Duality, in order to remain hidden from the Conduits, as they are unaware of such a realm existing. Inside of the realm, the 2 Forbidden Conduits taught their child everything that they know, in order to help Tertius understand what he can do with both of the sources that they inherited from both parents. And 100 years later, then began to practice on their Determination, in order to see what he is able to do. And the child, the child also began to grow in power, and they grew so powerful that they are able to possess the combined might of both of their parents, and are even stronger then them both, having 3 is the strongest sources of powers within him in existence. And eventually, when the time had come, both parents, seeing how much Tertius had grown and matured and how strong he has become, said one last goodbye to them, thinking that this will likely be the last time, as they went back to what they do in the past.

Tertius, as he watched the Eden Orbs involving the Undertale Multiverse, as well as with the Undertale AUs and ATs, he used it to try and learn how much he is able to do and became just as skilled in creation as both of his parents, and perhaps is even stronger then both parents in terms of his ability to create, and as he is a perfect balance of 3 Sources of Power, he does not suffer any of the drawbacks that happens with them, such as Cosmic Deflection and DT Demons and all that. He was a flawless Conduit of a sort.

But both Messiah and the Eldest Son of Pain, they both can feel his power, and they know he exists, they just don't know where. But Prism, the Forbidden Conduit of Disorder, knows of his existence, and went around in search of finding him, and eventually, he did when he accidentally stumbled into the Fields of Duality. When they met, Tertius is surprised, as he did not expect for someone to find out about this place. And luckily, Prism is a rather friendly visitor, as he and Tertius talked to one another for a bit. And during this, Prism revealed that Messiah and the Eldest Son of Pain are looking around to make them disappear, and also reveals that Tertius also has a half-sister named Anomaly!Core, who is just as strong and as powerful as he is. Hearing this, Tertius wants to go and find her, and while reluctant, Prism decides to do it, but they need to do it in a way that the Conduits do not find them. And luckily, Prism was able to bring Anomaly!Core into Tertius' realm, and needless to say, Anomaly!Core was rather happy, seeing that she has a half-sibling of her own to have. This surprised Tertius in how happy she is, but it didn't seem to mind this at all. 

They hung out with one another, with Tertius even entering the Alpha Timeline, and seeing all the various people that are present inside of the Alpha Timeline, and although he felt a bit lonely, Tertius does not feel that lonely anymore, and even admits that, knowing that he has a family member, is very sweet.

From that day, although Tertius would still stay inside of the Fields of Duality, he now visits his Half-Sister in the Alpha Timeline, and they hang out with one another, and in all honestly, Tertius feels like he is now much more alive then he ever was ever before.

Appearance:

Although being given a vessel, due to the Conduit of Time and Space using 100 as a host, Tertius possesses no physical form of its own. But as it is made of Determination, Cosmic Essence, and Nexus, he is able to take on the whatever form that they desire to make, and because of this, his appearances often can vary. The only thing that is consistent is the purple eyes that he gains when they make a body for them to inhabit for interact others with.

Personality:

Tertius is a rather unique individual, due to the way that it has been born. Tertius is a being of curiosity, wanting to make something new and wanting to see how much they can push their powers in order to know the full extent of their capabilities. He is also a person that is very creative and crafty, often making stuff such as AU and Multiverses, as well as making individuals in order to see what they will do, as well as allow them to evolve.

Despite this, he often felt lonely ever since the beginning of his life, as he feels like he is left behind by his parents, but knows that they mean well and want him to grow and evolve on his own, not to mention wanting to make him mentally mature, more then them, although Nicole isn't that much of a person that cares and is empathetic. But when he hears that he has a Half-Sibling in the form of Anomaly!Core, who is also a Forbidden Conduit, Tertius felt happy that he has another family member that is with him and is able to visit at any time he desire, wanting nothing more then to be with other people. Because of this, he feels much more alive and happier then before.

Powers and Abilities:

Cosmic Essence/Nexus Creation: Tertius, with his power over both Cosmic Essence and Nexus, is able to create anything that he wants, almost like he is Omnipotent to an extent, because of this, due to practicing with his parents, he is able to make anything, even dimensions of his own choosing. They can even make living beings.

Determination Detonation: Tertius is able to manipulate Determination to a dangerous extent, allowing him to make explosions so immense that it can even destroy an Eden Sphere.

Triality Arsenal: Tertius is able to make anything that they want in a fight, such as make a sword and shield made out of all 3 power sources at the same time.

Relationships:

Forbidden Conduits of Networks and Time and Space: The 2 Conduits that lead to his birth, Tertius has a stable relationship with both of his parents, due to the fact that they are able to teach him what they know. Although Networks is not a person of empathy, it didn't stop Tertius from having a good relationship with her to an extent. Tertius is saddened when he heard of the possible fate of his father, Time and Space.

Anomaly!Core: The Half-Sister of Tertius, both of the siblings never heard of one another's existence before and were not even aware of it until Prism introduced the both of them to one another. And seeing their own existences made them both rather happy to see one another. Nowadays, the both of them hang out with one another in the Alpha Timeline.

Forbidden Conduit of Disorder, Prism: Both Prism and Tertius are interested in one another, due to the fact that they are both Forbidden Conduits and are both extremely powerful, and because of this, both Prism and Tertius are often seen talking to one another about their days and all of that.

Bio-Conduit of Pre-Eminence, Merus: Prism introduced Merus to Tertius when he decides to come along with him, which surprised Tertius, as they have never heard of a Bio-Conduit before in the past. Ever since then, Merus and Tertius are shown to be able to hang out with one another and talk to one another.

Himmsworth: The TransVoid Being of Omniscience, Himmsworth and Tertius are able to get along with one another, although Tertius is admittedly a bit uneasy with Himmsworth, due to the fact that Himmsworth said his name even though they did not introduce themself to Himmsworth. But nevertheless, both Himmsworth and Tertius get along a little bit well.

Conduit!Cell and Mes: 2 Versions of Abyss that exist, Tertius is surprised to know of the fact that 2 versions of Abyss exist at the same time, which is something that he did not expect. But in spite of this, Tertius does not seem to mind then and gets along very well with the both of them.

Messiah and The Eldest Son of Pain: The 2 Entities that are responsible for the possible fate of his father, Tertius hates the both of them with a burning passion, and would want to see nothing more then to make them pay for what they have done, and even to this day, he has not given up on the vengeance that is within his very own soul.

Notes:

Tertius is so strong that the only Conduit that is able to match him is his own Half-Sister, Anomaly!Core, who is the Forbidden Conduit of Reality. They are both tied as the strongest Conduits in existence, to the point that the both of them are deemed unkillable by any known means.

The reason why he is able to house Determination along with Cosmic Essence and Nexus is because of the fact that, as Cosmic Essence and the Nexus are similar to the system of 0s and 1s in Binary Code. And the Determination is said to be the 0.5 in the code, which made the system stable inside of him. And thanks to that, because he has all 3 together, it made him flawless with no drawbacks on the Sources of Powers he uses.

Tertius has never met Edra or Falklore in the past. But he has heard of then through Merus and is interested to meet them if he is given the chance to do so.