Infinity is a Character I've had long before RWBY. The basic idea for him is he travels between dimensions filling plot holes and helping people. So this story does involve interdimensional travel, but most of the story is set in the world of remnant. But to truly understand his story in remnant you must first know his origins beyond that.

Legends

Stories have been part of society since the development of language. From simply explaining to someone else what happened during the day to legends explaining how things in the world came to be. These early narratives were passed from generation to generation orally or put down in the form of illustration. Eventually writing was created and the stories were put down in pen and paper. Stories have also grown more complex as society has, not just writing down what has happened but what could happen or even what could never happen in the world we know. People's imagination crafted entirely new places, people, societies, and worlds. This has only grown as media has evolved, from the creation of the printing press, to telling story through pictures, film, and animation. There are thousands if not millions or billions of fictional series in the world today in whatever medium they take.

But what if these stories weren't just 'fiction' what if they were real in some form or another. The multiverse theory suggests that there could be an infinite Amount of alternate universes besides our own. Some could be just like ours while others could be entirely different. If the butterfly effect is true and something as simple as what you have for breakfast today can create a parallel universe what could coming up with an entire other world in your head do?

Any work of 'fiction' could exist in the form of another universe parallel to our own. Legends have always been said to have a bit of truth to them after all. They could have really happened but were lost to history or happened in another world entirely. Whether it was someone's imagination that created that universe or if the story of that universe somehow came to them in a dream is impossible to tell but those stories could really exist somewhere, somehow. Theories also exist of the possibility of traveling between these dimensions which could also explain how we would know about these different universes in the form of fiction. These are countless works of fiction about people traveling to different worlds or two or more worlds colliding in what is known as crossovers.

This is a story not of going from one world to another but one that is woven throughout the others. It takes places between the pages of paper book, throughout the lines of digital stories and hidden in the frames of moving pictures. This is the story of someone that wouldn't show up on a list of characters or be mentioned in any events but whose presence can be felt though the results of their actions. They travel off-screen of the major events of a story, working behind the scenes to make sure things go a certain way, filling in the blanks and helping from the darkness.

In the scheme of the multiverse this is the legend of a shadow, traveling through the void between dimensions

As with many legends things did not start out this way. They had to start somewhere originating from their own time and place. The story begins in a world not unlike our own, but like most parallel universe with something changed. In this world people began developing powers within a certain area. It was seeming random who got them and no one knew why it was happening. One of the first was a young boy who had been born with a slight brain injury that made his right side less sensitive and right hand unable to do dexterous things. He grew up adapting to do things differently mostly with his left hand. What he lacked in physical ability he made up for with an overactive imagination to come up with different ways to solve problems. The power he developed was based around this imagination. He was able to turn matter into other things he imagined, allowing him to make tools and technology of his own design. The saw his powers as a gift decided to use them to help people. Unfortunately not everyone that developed powers shared this ideal. Some decided to use their powers for their own gain and became villains. . The boy who had always admired heroes of fiction used his powers to create armor and weapons to counter those with powers and protect people. With his powers stemming from the infinite human imagination he gained the name "Infinity" Though these villains were few compared to most with powers who wanted to live a normal life the rest of society started seeing them as dangerous. Even those that used their powers for good like Infinity were seen as a threat. He was undeterred by this and instead imagined a world where those who had powers could live in peace with the rest of society. He formed friendships with others like him and they worked together to fight evil and protect the innocent. But while this battle of society raged another struggle was taking place. A strange substance began showing up in the same area that people were developing powers. This substance was dangerous to most but Infinity was able to use it as a catalyst for his transmutation so he began investigating into it so he could gather it up and keep it from hurting others. It led him and his friends to an ancient temple like structure underneath a nearby mountain that had been reactivated just before people began being born with powers. The temple for some reason reacted to Infinity's powers and a portal appeared in the center of the structure. It began to grow unstable and more rifts opened up all around the area, threatening to destroy everything. Unable to figure out how to deactivate the temple Infinity reasoned that since he activated the structure that to stop it he had to enter the strange portal, having no idea what would happen to him. He stepped through and the portal closed, no one knowing what became of him.

He woke up in another place having no idea where he was. He soon discovered he had been transported to another world entirely with no idea of how to get home. So he did what he had always done used his powers to adapt and helping people. Later another portal opened before him and he was transported to another world and so forth. Some of the universes he began recognizing as series he had read or seen and thus knew how things worked there and what happened down the line. He used this knowledge to help things move along as they should but also save as many lives as he could along the way. In each universe he gained new skills and more knowledge about the multiverse. He eventually ended up back in his own universe not long after he had disappeared, though it had been months for him. He continued to travel between different dimensions, having no control over the portals, just going with the flow of where the multiverse sent him. This is how his legend was made. He traveled to countless worlds, spending dozens of lifetimes because traveling through the portals messed up his physical timeline. He could come out as a child, how old he was in his own world (twenty's) or even an old man. I could describe his countless adventures but it would be like going though whole sections of libraries, and movie stores.

So instead I will describe key events of his journey.

When things changed.

The first was when an ancient evil was released from the cage it had been sealed away in for eons. It was a shapeless parasite that called itself Abyss. It would take over a powerful host to feed on its energy and then projected itself outward as a black inky substance. Its desire was to consume and would engulf the universe and beyond if it could. Infinity arrived when it was unleashed and tried to help the naive people fight it. Abyss sensed Infinity's power and attempted to take him over but Infinity's will was too strong and he was able to suppress Abyss, forcing him out. Infinity then tried to defeat Abyss but physical attacks did not work on him and he could regenerate from any part that was left of him. With no other options to deal with the parasite the natives used an ancient technique to seal Abyss inside Infinity who was the only one there to be able to suppress him. Infinity then had to carry the burden of Abyss wherever he went. If he lost control of his emotions or became too injured Abyss could take over and cause havoc until Infinity was able to suppress him again. Being that Infinity was his host Abyss did give Infinity increased healing to keep him alive but Infinity only saw Abyss as a burden that was his duty to control.

The next major event was when Infinity met a certain someone. Being hundreds of years old, as well as having to deal with abyss Infinity never thought he would meet someone he could fall in love with. But he then ended up in a world where there were beings that lived hundreds of years. He ended up in a universe similar to the 'Bleach' universe where Shinigami slayed evil spirits known as hollows. What differed from the normal bleach universe was instead of a separate "soul society" the spirit world existed parallel to the human world, certain parts being where sprits reside. The Shinigami were like a bridge between the two worlds, able to live in both. This is where he met a Shinigami Kunoichi named Yuzuki who was an alternate version to a character in the main Bleach, Yoruichi. Like in the main universe she has Purple hair, Yellow eyes and is a somewhat rogue Shinigami skilled in stealth and hand to hand combat. In this parallel world however she is also skilled cat burglar who steals for fun and a challenge. They met when she was assigned to teach him how to use his zanpakuto powers. He was already skilled in swordsmanship and hand to hand combat so they soon became training partners instead of teacher and student. Being the first man able to match her in hand to hand combat Yuzuki began to admire Infinity and they eventually fell in love. However when Abyss was released unexpectedly and Yuzuki hurt because of it Infinity left, thinking it better to not put her in further danger. Yuzuki goes after him, though terrified of what Abyss is but wanting answers from Infinity himself. When she eventually finds him he explains how he had to have Abyss sealed away inside him and she sees he was doing what he always does. Putting himself in harm's way to protect others. Yuzuki then begins occasionally travelling with Infinity, in a way helping him keep Abyss under control and becoming his lifelong companion.

And this brings us to the next major event in Infinity's story. As before it is when change happens.

Cages grow old and evil left to fester grows

Something was bound to break…