Disclaimer: I do not own Yu-Gi-Oh! or any of its characters. If I did, at the very least Atem and Yugi would've hugged in the last chapter/episode.

Definition

How could you even begin to describe what they had?

Was there anyone else in the universe who had been as intertwined and connected as they were? Was there anyone who had felt as strongly as they had, who had given as much as they had for each other?

Yugi didn't know. He certainly felt like there was nothing that could ever compare to what he and his other self had, but there was no way to be certain.

And unfortunately, people seemed to require labels for everything.

The others had gotten that his and his other self's relationship couldn't be defined. For the most part. Bakura probably got it the most, though his own relationship with the spirit of the Ring ended up being mostly a manipulation. Jounouchi had just let them do their own thing, understanding that they were close and important to each other and left it at that. Honda also had the same sort of assumption.

It was Anzu, who had known the best of them all that the two were close, that had asked him what the exact nature of their relationship had been. She had been within her rights to ask as Yugi had turned down furthering their relationship beyond friendship.

Yugi had love his other – Atem. He had loved him like he had never loved anyone before or since or probably ever would. Atem had never said anything, but he knew that the feelings were returned just as strongly.

But neither of them had ever really said anything. There had never been a need to, when they could literally feel what the other felt. Plus, they knew that to do anything more would just make things even more painful down the line.

Though sometimes Yugi wondered how it could have been any more painful than it already was.

They had never labeled it, but as Yugi sat back and looked up through the window in his room, he felt it wouldn't do any more harm to try to suss it out now, if only so he would be ready for the next time someone asked.

His Other Self

That was what they had thought Atem was at first. Another Yugi, another aspect of himself that had been brought to life by the will of the Millennium Puzzle. A person so different and yet so like himself.

Yugi was shy and never stood up for himself. His other self was bold, easily calling out those who would harm them. His other self had protected him, even though Yugi had been afraid of what had been happening around him.

It was at Death-T that they truly met each other, and it was only after that they began to realize that they were not one and the same, mere reflections of each other, but two entirely different people.

But to reflect the bond and body they shared, Yugi had still referred to Atem as his other self.

Partners

Atem had been the first to call them partners, "aibou" becoming the way that he generally referred to Yugi.

When they dueled Pegasus, it had been the first time they truly worked together, and they had found that they were incredibly in sync. They could read the other like no one else could, and it helped in all areas that they were together.

Their partnership opened so many doors between them, and for the first time, they really had a "relationship" as more than just being another self to the other.

Yugi had always felt a thrill of pride whenever Atem had called him "aibou."

Friends

Yugi had wished upon the Puzzle for friends, ones who he could rely on and who could rely on him. Atem always argued that Yugi managed to form his friendships with Jounouchi, Honda, and Bakura, as well as restored his friendship with Anzu, all on his own merit, not because of him. However, Yugi knew that there was at least one friend that he had that he could thank the Puzzle for.

Atem was his best friend. The two of them had understood each other the best, and Yugi liked to think that it wasn't just because they shared a body and mind.

They simply got each other, even when they had to explain their actions to each other.

Their friendship had begun even before their partnership, but it was as they found equal footing with each other that it truly flourished. Yugi had always been certain, even with the inevitable hiccups that all relationships had, that Atem would have his back and he would always be there for him in return.

Yugi knew he would never have a friend as close as Atem, even with how dearly he loved his other friends.

Brothers

In a way, they had also been like family to each other. It made sense as they did live with each other.

Atem would tease Yugi on his style and about the crush he once had on Anzu. In return, Yugi teased him with whatever facts on Ancient Egypt he could find, his other self swearing that he himself would never do such things described. And together, they had tried to support each other with the social awkwardness they both shared, though Atem's was only ever evident when not dueling.

They had figured out a way to play games together. Sometimes one would be in control with the other watching. Other times, they would play together by forming strategies as they went through the game. There were also the times they would play against each other, with the one in control moving the pieces for the other or just trying to one-up the other's score.

They had laughed and joked around like any other brothers would. Yugi's mom had never seemed to figure things out, but as it turned out Grandpa had known all along, and somehow Yugi knew that he had considered Atem family as well.

Lovers

…

Yugi knew that they had never admitted to anything, but he had known that what they felt for each other was stronger than any friendship or familial relation.

But things wouldn't have been able to work out with the way things were. Maybe they could have found something, but…they never tried.

Maybe in a different life…

Soulmates

This was close to what they were; it was a fairly accurate term for what they had been. After all, they had completed each other. They had each made up for the other's weaknesses, being strong where the other lacked. They knew each other in a way no one ever could. They were connected by their very souls.

And wasn't that supposed to be what your soulmate was? The person, no matter if the relationship was platonic, familial, or romantic, that helped no matter what, that completed you, that made you feel like you were on top of the world, that understood better than anyone.

If that was the case, Yugi had no doubt that he and Atem were soulmates. Even with the 3000-year gap, fate had brought them together. It had felt right, and it was like they were made for each other.

Of course, that just made everything hurt worse, now that they were parted.

Though now that he thought about it, those words reminded him of something…

It was from a sci-fi show and movie series that Jounouchi and Honda were interested in…

"Parted from me and never parted…"

It certainly fit the best.

The two of them had been separated several times even before their final parting. Yet each time they had managed to find their way back to each other. No one could really keep them apart.

Even now, they may be parted, but a part of Atem would always be with Yugi, just as part of him would be with Atem.

"Never and always touching and touched."

The thing was, Yugi and Atem only ever really touched once.

When one of them materialized while the other was in control, they did sort of touch, with a lingering, prickling feeling appearing where the spectral hand met flesh. It was more of a sensation than a touch.

Both while meeting in their soul rooms and in the Millennium World, neither of them technically had bodies. They were touching with their souls, which some might consider to be even more intimate than a normal casual touch. It felt like they were touching for real, but that was only because that's what their minds were telling them.

They thought that that was the closest they'd ever get.

It was only at the end of that final duel, as Atem placed his hand on Yugi's shoulder, that they actually touched.

Yugi still remembered it.

T'hy'la

That was the term from the series. Friend, brother, lover, it meant all of those things at once, and it certainly seemed to fit best out of all them.

It wasn't exactly right, but it was probably the closest Yugi would get. It did encompass all of the types of love that Yugi had felt for Atem and how Atem had felt in return.

Still, if someone were to ask, he probably wouldn't go into all of this. Figuring all of this out was more for his benefit than anyone else's. No matter who it was, he still would tell them nothing more than Atem was the person closest to him and would always be that. His friends already knew that well enough to get what he meant.

That's why he didn't think he could ever be in a relationship, even if it were with Anzu. He was glad that she understood that, though she didn't quite get it.

Besides, if there was one thing that Yugi held on to, it was that he and Atem would meet again. No matter what, they always found each other.

So, despite how much it hurt, Yugi would continue on, though his friends' companionship did help just a little bit.

But still Yugi couldn't keep back the little smile on his face as he got ready for bed.

Because sometimes it did help a bit to have a word for what you are.

AN: I know that as a generation, millennials try to shy away from definitions and labels. Personally, I don't mind them as long as its yourself whose sticking the label on, because as noted above, it can be comforting to have a word for a particular feeling or being. I remember thinking something was wrong with me until I discovered asexuality, and then I was so glad that there was a word for what I was and that I wasn't just a failure of a human being.

So this was born from my own musings about Atem and Yugi's relationship. I've been a Puzzleshipper since back in high school when I first watched this, but upon rewatching Star Trek TOS, I was like, "You know, I'm pretty sure those two are t'hy'la." I also tried to muse on how each part fit into their relationship too. I can get most interpretations of them (though I would like to point out that pretty much all the materials points out how they're closer than just friends) except for where Atem's a fatherly figure, because a) Atem may act mature but he was only like 17 or 18 when he died, b) those 3000/5000 years don't count because he was asleep essentially, and c) you can see he's not really a fatherly figure because outside a duel he is obviously a teenage dork. So yeah.

Anyway, I hope you enjoyed this. At the very least I think they were soulmates no matter if you consider them platonic, familial, or romantic partners.