I haven't written an omake in a while, so here's something I thre together in 10 minutes. I hope it an't too bad.
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It happened on occasion. Every night he would have dreams, visions. His unique existence as an Angel allowed him a glimpse into other worlds, but at night he often wandered unintentionally while he dreamed. Normally though, it was no different then dreaming. These worlds couldn't see him and he couldn't interact at all. Merely a witness to that world's events. Normally...
He found himself is a swamp. Mud and moss surrounded him and every step submerged his feet entirely. He was wearing his school uniform, which he clearly did not go to bed with. It wasn't like any of his other wandering as he felt his actions. He felt the humid air as he marched, he felt the wet mud beneath him, and he left footprints in the swamp.
"Well, well, well. Not often I get guests like this." A deep voice, with a hint of amusement spoke. It was loud and clear, but Kaworu could not see where it came from.
"Where are you? Where am I?"
*SPLASH*
Something huge bursts out of the water and land several meters in front of the troubled man. It was a large beast, with bright yellow eyes. It had the appearance of a giant catfish, but dressed as a facy gambler. As fancy as clothes tathered and ruined my mud could be.
"With pleasure. I am the River king, and this is my domain. I offer a warm welcome...Tabris."
Kaworu frowns. "That's not my name."
"I beg to differ." The beast moved its gaping maw, and smirked. Kaworu knew it was pointless to argue, it likely enjoyed how uncomfortable that name made him.
"Why have you trapped me here?"
"What gave you that conclusion?"
"I've been trying to leave, but i can't. Something is holding me back."
The beasts smile grew and Kaworu finally got to see its teeth. Large and sharp, a shark would be jealous.
"Good assessment, yes I am holding you here, but to be fair you came here all on your own. Is it wrong to hold a home invader to account when he trespasses?"
"No, that's fair. And in that case I apologize for my actions." Kaworu's words were genuine. Considering the lengths his fellow pilots and himself would have gone in a similar situation, he figures the initial hostility was born due to his actions.
"Your intrusion was more entertaining then insulting. So I accept your apology." The beast tips its hat. "However, while you are here..."
Kaworu tenses as he knows he's on the back foot with this being.
"... It would be remiss of me to pass up on making you an offer."
"An... offer?"
"Yes. For a once in an eternity deal." The beast closes the distance slowly, his arms in a open posture to show he is non-hostile. Kaworu waits for him to continue, but when its clear the beast was waiting for a response he nods his head to gestures him to continue."As I said, I am the River King. And I am a being capable of roaming the rivers of time and space unimpeded. The dadric sea is but a kiddy pool for me."
"O..k..."
"It means, that I can fulfill any desire asked of me. Including yours..."
Thump thump
"What do you..."
"I've seen the way your eyes wander. The way your souls yearns to know and understand what it was not designed to. The small envy feel as you watch those that you love experience life more than you. How it takes a mile of marching to match a single step from them."
Thump thump
"Tabris, I can offer your deepest desire. I can make you human."
Silence. Only the sound of bugs and frogs can be heard. Kaworu for his part was stunned, his eyes opened wide and his face was of shock and suprise.
"Lies! You cannot... that's impossible!" Kaworu finally speaks, but panic fills his voice.
"I can understand the scepticism, under most circumstances you'd be right. But I play by a different set of rules. It wouldn't be painless, but I promise at the end, you'd be human."
"What... what do you want?"
The beast grins. "Normally, I'd ask for you to let me in, but in your case you have something better. Your solenoid. Infinite energy has its perks and for you its practically free since humans don't have one."
"I... I..."
"No need for pressure. A decision like this takes time to make, plus I'd figure you'd want to discuss this with your 'better half' as it were."
Kaworu nods. He almost certainly wanted Rei's opinion. She would have the answer.
"Here," the beast takes off its hat and pulls a card out of it. Despite the filth covering said hat, the business card was clean. It read Tahm Kench, the river king and nothing else but weird markings. Was that the beasts name? Kaworu thought.
"Use this card in combination with your ability, and it'll bring you right back here. However, my offer isn't forever. By tomorrow night the card will vanish and our business will be through."
Kaworu looks at the card once more befor turning back to the beast.
"So think about it. And don't forget. You need to.."
‐-------
"...wake up!" Familar red eyes replace the frightening yellow and Kaworu's beloved comes into view. With nothing but their blanket to keep them modest, Kaworu remembers the night before and their act of passion.
"Good morning Rei."
"You worried me. You were tossing and turning and your soul was twisting in on itself. I hadn't seen it get that bad since we destroyed they last fragment of adam." Rei got up to get dressed as she spoke. Mindful to keep her back to her love. He wanted him to hear her, not blank out due to the show.
That would be for latter.
"I had a nightmare. It was... harrowing."
Rei turns to see her love and notices how bothered he is. To the point where his love was bare before him and he had no reaction. So she went for a hug.
"Do not worry yourself. It was only a dream. Come, we want to get dressed. Shinji is making breakfest. He wanted to show off what he learned from his cooking lessons."
"Cooking lessons? Shinji? Isnt he already an envy of 5 star chefs?" Kaworu smiled, proud of his friend.
"Yes, but he apparently found someone better and is under his tutelage. A Emia...or was is Emiya? Regardless, nows the time to see the fruits of his endevours!" By now Rei was fully dressed and ready to go.
"Ok, give a minute to get up and dressed myself. I am curious to see what changed."
"Ok..oh and Trout."
"Ye-" Rei kisses him silencing his response.
"Don't let it it get to you, I'll always be by your side."
"Ok. Thank you." Rei leaves the room to join the other appartment. Kaworu gets up and begins to get dressed, when he notices something in his pocket that was supposed to be empty.
A business card.