Disclaimer: I'll save us all time and just say I don't own it and this is completely non-profit. However, I did think up what is mentioned of Yuugi's backstory here. Don't copy me without permission, please. I'll probably let you use it if you ask. :)

Note: Most of these have no timeline, but 18 and 19 are intended to be around the episode of season 0/manga chapter with the dragon tiles. Can't remember the episode or chapter numbers right now. You don't have to have seen the episode or read the chapter, anyway. Also, 23, 24, and 25 are all right in a row within a day. The rest is up to your imagination.

1: Lighthouse
He would not realize until long afterward that the thing that had softened him enough to offer a hand to his enemies was the same beacon of light that first drew him, lost and lonely and teetering on the edge of sanity, out of the darkness.

2: Foundling*
He wondered where his host's parents were sometimes, because he'd never seen them; when he caught a glimpse of a thought in the boy's mind, he was furious, because he knew no sort of monster that abandoned his family and ignored the phone calls of his little seven-year-old son saying that his mother was closer and closer to suicide every day; and he swore to himself that he wouldn't abandon the boy.

3: Fifteen
Though he was aware that he was probably several thousand years old since the Puzzle had been found in an ancient Egyptian Pharaoh's tomb, sometimes the job of putting villains away was a little overwhelming for someone who couldn't have been more than fifteen - but then he remembered his host and his host's friends, and his reason for continuing to exist, and he shouldered the burden and walked on, feeling the weight heavy on his heart.

4: Chirp
He didn't sleep, so when his host woke up in the mornings, he always felt it; then he wondered how the boy could practically bound down the stairs at such an early hour and chirp, of all things, a "good morning" at his grandfather, because he really wished he could sleep most days.

5: Paternalism
The boy's father showed up one day, intrusive and demanding, and the boy was not angry but he was in pain; and that alone sent him into a destructive rage.

6: Apparition
Sometimes he thought he could remember something, something, from his past, and he reached for it, strained to make the wisps of memory take a recognizable form; but the wisps gave way under his mental touch and he was left in the shadows, chasing after nothing, alone.

7: Desecration
When he was in control and among the boy's friends - not his friends, he reminded himself, don't get attached, can't afford to lose - he sometimes felt as though he were treading on something sacred, some holy bond that such a dark and near-murderous being (near enough, for he'd sent many souls to their eternal suffering) had no right to be near, let alone in the midst of.

8: Harmonic
It struck him sometimes that he and the boy were like pieces of the very Puzzle around their neck, fitted together perfectly, two halves of a whole, one of which without the other may perhaps function, but never truly accomplish completion; and it instilled a deep fear in him, for he wondered what would happen if ever the Puzzle - if ever they - were broken apart.

9: Excerpt
He only caught snippets of what went on around him, and it wasn't enough for him to feel like he was really living like he ought to, and sometimes he would resent that fact; then he reminded himself that the boy in whose body he now resided had saved him and he was horrified by his thoughts, and he clung to the tiny excerpts of life that he was receiving and was very grateful, for he knew that the boy could easily separate them if he wished.

10: Insanity
He tried not to think about the days and hours and excruciatingly long moments spent waiting in the nothing before the Puzzle's completion, but sometimes those little whispers would worm their way into his head as he bode in the darkness of his soul room, waiting for morning, praying for morning; they would remind him that this wasn't real, couldn't be real, had to be his imagination, a dream, because no one would ever save a demon like him.

11: Peril
He didn't usually pause to contemplate exactly why cruel and evil beings, moral senses overridden by whatever their choice of evil, were so drawn to himself and his host and even his host's friends, but as he finally rid the world of what had to be the fifteenth evil in under three weeks, he glanced over his shoulder, a thought running through his mind that may have been akin to, Does the universe have it out for us?

12: Sundown
Afterdark frightened him, though he was loathe to admit it; it created a thin but near-tangible barrier between himself and his host, his only connection to reality, and he feared the coming of night more than anything.

13: Unmasking
When the boy appeared in his soul room, mystified by the strange place and with the rest of his sleeping hours to spare, they settled down on the cold, hard stone floor for a nice, long session of getting to know one another; and at first, he expected nothing to come from it, but by the end, he was feeling like layers of his heart - of masks - had been stripped away painfully, and the boy knew his weaknesses better than he should; and he worried, because he knew that no one could be trusted, even his other self.

14: Muse
He sometimes caught his host pondering things that were totally inconsequential; and at first, he didn't understand why, but when he caught himself doing it as the boy slept, he finally realized: it was to occupy the mind away from the horror of deep thought.

15: Misadventure
Of course they ran into trouble the second time they went to Kaibaland - a genuinely sociopathic guy with a gun, again - and he wished that the madness would stop already so that his host could be halfway normal.

16: Transparency
His host could see through any wall he put up, could feel what he was feeling, and though sometimes he did not want the boy to feel it, to know it, it felt good when the boy offered wordless comfort.

17: Curb
The irritating teachers said the exact wrong thing sometimes, and his host took the criticism poorly; it was at this point that the spirit learned to seal away his anger to be channeled into bigger threats later on, because his host would not appreciate his tactless-not-evil teachers receiving a penalty game.

18: Prayer
The first time his host's soul was ripped out of his body, the spirit was just barely able to reach the Puzzle and take over; during the following game, he found himself reciting a prayer to a god he wasn't sure he believed in to help him return the sacred half of himself.

19: Tactic
The second time the boy managed to get into his soul room, they spent the night in an odd, comforting quiet, playing a very simple game to immerse their minds deep in simple monotony; discussing the almost-loss of both their souls was not something that the dark half wished to do, and the only tactic he knew to avoid this topic was to avoid any topic at all.

20: Knowing
In the midst of daily life, sometimes he found the opportunity to probe his host with a feeling of confusion at something he was doing, and the boy would explain it happily, but that didn't stop him from feeling embarrassed for not knowing such basic things; of course, the boy also felt his embarrassment, and was quick to reassure him; and the show of caring always made the spirit feel strangely...tender.

21: Waiting
It didn't even occur to him to unearth his lost memories until long after he was freed - after so long waiting in the darkness, his mind had been worn away like hieroglyphics under the harsh desert sands, and when he found a purpose, it did not matter if he had to wait forever so long as he was not alone.

22: Profession
"You know, I think you could make a career of playing games," said his boy suddenly one night in his soul room; he blinked dumbfoundedly back, unsure what to make of this, and the boy laughed.

23: Childhood
His boy was called in to see the school's guidance counselor - some sort of routine thing - and when it came to questions about his childhood, he felt his host lying through his teeth, saying that he'd been very happy during it while the agonizing, gaping wounds in his heart opened a little wider with each word, as if struck by the soft tones of his voice.

24: Fear
That night was tense and silent in his soul room; his boy didn't understand why, and the spirit didn't, either, until he realized that the strange creeping sense of pain was fear - fear of breaking his promise to himself not to abandon the boy, fear that he would soon wake up and this precious purpose, this precious light, would have slipped away from him.

25: Tomorrow
He did not know if he would be there forever, but he would make tomorrow count, even though that fear-chill would never fully vanish from where it had settled on his shoulders.

Title: n., a relationship, especially one of mutual trust or emotional affinity. I associate this with the word "harmony," which does not mean that two things are alike, but that they fit together. These are the two words closest to how I'd describe Yami and Yuugi's relationship, a harmonious rapport.

* Foundling: A foundling is a small child found without a parent or guardian. It doesn't fit the backstory I came up with for Yuugi perfectly, but it was what came up, and I wanted to be a little more original with his backstory rather than just having him be an abandoned child who was found by Grandpa Mutou.

A/N: I was going to do 50 themes, but I wanted this up before I leave for vacation. Maybe I'll do another 25 from Yuugi and his side of the friendship later. Anyway, every word I used came from a random word generator. I did skip a few, but most of them stuck.

I'll expand on most of these if I'm asked to. Go ahead and ask if you want me to! I'll do my best. You can also give me prompts or challenges of your own. ;D

I was going to post this on Christmas for the sake of posting it on Christmas, but that doesn't look like it'll work out since I'll be on vacation with no access to my computer. Anyway, merry Christmas, and happy holidays! I won't be here for New Years, either, so happy New Year! Please review!

- Nitro