Hello! This is a OS, and a RengerXAhri, I know It's not every day you saw a story about those two together, but let's give a try, no?
I don't know if I will convince some people that they can make a couple, but I will try my best.
I'm French, so my English is not perfect, so if you have some advice, please review.

It was the end of the day, every champion could finally returned to their other activities, and have some rest, but only Rengar the pridestalker remained near the Summoner's rift's teleporter, when all champions left, he took the teleporter. He arrived near the blue nexus, and walked toward the middle lane, why Rengar was here, was a complete mystery for all champions, no one know he was going to the summoner's rift sometime. Rengar stopped at the middle of the lane where every middle champion fought at every beginning of all matches. He looked at the dark sky, and stared at all stars that shine in it. Rengar closed his eye, and smelled the environment, he could only smell the blood of every champion who died here, but something was wrong, he wasn't alone, Rengar sighed.
"I know you're here, Kha'Zix" Rengar turn around, and Kha'Zix appeared in front of him.
"What do you want?"

"I was thinking, we can have a little talk, between old friends." responded Kha'Zix

"I don't want to fight you. We fight all day, just give me a break." said Rengar

Rengar knowing that Kha'Zix, will continued to insist, he decided to returned to the blue nexus, after Rengar passed Kha'Zix, he heard him preparing his claws. Kha'Zix jumped on Rengar, but he easily dodged his attack, he sighed, and took his weapons out. They started to fight each other, Rengar had the advantage, but Kha'Zix continued to attack, he had no strategic, he was just attacking and kept attacking, when Kha'Zix finally hit Rengar, he jump back and stopped attacking.

"You finally come to your sense." declared Rengar

"No, it's just… I'm sure that I won the battle." Said Kha'Zix, he was licking his lips, like he was preparing for eating something.

Rengar didn't like the sound of his phrase, and the way he was acting, Kha'Zix was full of injures, but Rengar had only one injure on his left arm, Rengar decided to run away, but when he turned around, he felt his body was heavy, he couldn't move anymore. Rengar's heavy body fall on the floor, his face was stuck on the ground. Rengar tried to move but it was useless, he finally heard Kha'Zix's footsteps behind him.

"Looks like the poison really work." Spoke Kha'Zix

"Poi… son?" asked Rengar

"I asked some friend in the league to prepare a poison. This poison can paralyzed everything, for a very, very…very long time, and plus he can't be detected by the smell, so I was sure you will not find out." Kha'Zix looked at Rengar's body, his saliva was drooling from his mouth
"Well… I think I can say…" He approached his head near Rengar's ears.
"Dinner is serve."

"Din… ner?" asked Rengar

Kha'Zix didn't responded, he slowly took off Rengar's armor, when Rengar's armor was finally off, Kha'Zix crossed his arms

"Should I start with one of your arms or legs?" asked Kha'Zix
Rengar didn't responded, and tried to move his body.
"Leg… yeah, you're right."

Kha'Zix grabbed Rengar's left leg, and plunged his teeth into Rengar's leg, even with the poison Rengar could feel Kha'Zix's teeth inside his leg. Kha'Zix pulled the flesh which he had taken with his teeth, Rengar clenched his teeth, he just have to waited for his death and his body will recovered, but for now Rengar have to resisted.

"You are delicious. It's better to eat is prey when she is alive." declared Kha'Zix

Kha'Zix continued to eat Rengar's leg. The time passed but the poison was still infected Rengar's body. Rengar was wondering how many time passed since Kha'Zix started eating is leg, after a little time Kha'Zix sat on Rengar's back and bite his right shoulder. Rengar once again clenched his teeth for not letting a roar escaping from his mouth. Kha'Zix took only one bite, but he suddenly stopped, and sighed.
"You are really good, but I'm getting bored. I want to hear your suffering. I want you to roar, to pleaded, well if my method doesn't work, I will change them."
Kha'Zix grabbed Rengar's right arm and began to twist it, Rengar didn't understand what he was doing, but started to understand when his bones began to crack, he could see his skin tearing near his shoulder, blood began to spatter between his tearing. Kha'Zix started to pulled his arm, Rengar was trying to move his arm, but he couldn't. Kha'Zix finally took off Rengar's arm, but Rengar didn't let a roar escaping from his mouth. Kha'Zix began to get mad, he took the arm that he just took off, and started to hit Rengar's head with it. After some hits, Rengar's head was cover by his own blood.

"You're not funny Rengar." Said Kha'Zix
He thrown Rengar's arm away, and he turned Rengar's body
"One leg, one arm, then I will take your eye"

Kha'Zix approached his mouth, toward Rengar's eye. Rengar immediately closed his eye, he felt Kha'Zix's tongue licking his eyelid, saliva flowed on his face. He could smell his blood in Kha'Zix"s breath. Rengar slowly opened his mouth, ready to pleaded.

"Hey Kha'Zix, look over here!" yelled a voice

Kha'Zix raised his head, and Rengar opened his eye. Suddenly Kha'Zix was thrown away, by an orb. Kha'Zix immediately run away, he had taken too much damage. Rengar heard footsteps next to him, he tried to move his head, but it was impossible. Suddenly, a face showed itself in front of his face.

"Hello Rengar, it's not every day than people can see you like this, but don't worry, I will help you." declared Ahri

Ahri grabbed the dagger next to her, and pierced Rengar's chest with it. Suddenly Rengar slowly disappeared, he was finally dead. She could see his soul going away. No one was scared of death anymore, because of the protection of all summoners, but he was still strange to see someone dead coming back to life, or feeling death again and again. Ahri sighed and decided to return to the nexus, and met with Rengar for asking him a favor since she saved him from Kha'Zix...more or less. When she turned around, Kha'Zix was in front of her.

"Hey Kha'Zix, I thought you had run away." said Ahri

"Well, you took my prey away, so I had to find another one. I never eat a fox girl before." Declared Kha'Zix
Kha'Zix still have some poison on his claws, he just have to hit Ahri one time, he moved his leg for making a jump, but suddenly he couldn't feel his leg anymore, and everything went black.

"Rengar I could do this by myself you know." expressed Ahri

"If he had touch you, you would have finish like me." declared Rengar
Rengar had Kha'Zix's head in his hand, and she suddenly disappeared. Rengar was angry for some reason. He shook his head and looked at Ahri.
"Well now I think, I pay my debt. You saved me, and I saved you."

"I was thinking, I could ask you something in exchange, well too bad. Anyway, what are you doing here?" asked Ahri

"I could ask you the same question." responded Rengar

"I asked first." said Ahri

"Ladies first" expressed Rengar

The two of them were looking at each other, no one will move until someone will say something.

"Fine, I came here, because after I received 10 invitations for a restaurant, 5 for … bedtime. I wanted to be alone for a bit, so I came here, thinking there will be no people here, but I was wrong. Now your turn." responded Ahri

Rengar didn't say anything, and just looked at the sky. Ahri raised her head.

"The stars?" asked Ahri

"When I look at them, I feel like... I'm home." responded Rengar

"Your home misses you." said Ahri

"Not you?" asked Rengar

"My home is gone the day I decided to follow my dream," responded Ahri

Ahri raised her head again, but rengar was still looking at her, she was following her dream for becoming human, but everytime he was looking at her, he could only felt sadness, she was always happy, smiling at every champions, but she was actually sad.

"You're sad, because you reject the fox who is inside of you." declared Rengar

Ahri frozen at rengar's words, she looked at him and forced a smile,

"No... you are wrong. I'm not sad," whispered Ahri

"Looks like. I'm right." expressed Rengar

"No! You're wrong!" yelled Ahri

Ahri suddenly covered her ears, and closed her eyes. She was scared,Rengar slowly walked toward her, and grabbed her hands.

"You are lucky, you know that." whispered Rengar
Ahri was surprised by what Rengar said, she slowly opened her eyes and looked into his only eye.
"You know who you really are, your origin, your family...me... I don't know anything. I can't remember it, even my name. Rengar is the name that the human who adopt me gave to me. Ahri even if you become human, you will never forget who you really are, you will not forget the fox you used to be, or what you are now."

"It's... not that" whispered Ahri

Ahri moved back, and started to walked away. Rengar bend his head, thinking about something. Suddenly he run toward Ahri, grabbed her right hand, and guided her into the jungle.

"Rengar, what are you doing?" asked Ahri

Rengar didn't respond. Ahri didn't try to resist, she was too curious about where Rengar was taking her. Rengar finally stopped in front of the Nashor's place. He sat down, and looked at Ahri. She immediately understand that he was a invitation for her to sit next to him. Ahri sighed, and sat next to him. After ahri sat down, Rengar looked at where the Nashor was during every battle, the Nashor wasn't there, even him took some rest like all champion. Ahri followed his gaze, but nothing was happening, Ahri was wondering what Rengar wanted her to see. They fought here all day, if something special was there, they will have noticed it earlier. Ahri finally get up and looked at Rengar with an angry face.

"Rengar what do you really want?! There is nothing here!" Ahri suddenly blushed
"If you want to pass some time with me you just need to ask..."

"Hunter learn to be patient, just wait a little longer and your prey will be here." responded Rengar

Ahri looked one more time, and suddenly something catches her eyes, a little red flower. It was impossible that vegetation can grow around the nashor, but other flowers appeared. Ahri coundn't believe what she was seeing in no time the Nashor's place was full of red flowers. Rengar got up and offered his hand to Ahri. She took it, and he guided her in the middle of the field, Rengar released Ahri's hand and lie down on the ground. Ahri sat next to him and looked at all the flowers aound her.

"How it's possible? I was thinking that vegetation could not grow because of the Nashor's poison." said Ahri

"Ask Zyra if you want to know everything about flowers. I think they arrived to find a way to survive. Humanity can do this, so why not flowers." declared Rengar

Ahri looked closely at the color of all flowers, and something surprised her
"They are red like..."

"Blood." finished Rengar
"Those flower grow every night. I was really surprised by there color, but I think when we die here maybe when we lost some of our blood they absorb it, in some way."

"It could explain there color, but the reason they grow..." said Ahri

"I don't know." expressed Rengar

"How many people know this place?" asked Ahri

"I'm the only person who know about this, and I prefer to keep this, as a secret." responded Rengar

" So... why me?" asked Ahri

Rengar sighed, and continued to looked at the sky.
"You know, I want to know who I am, but I'm scared. I did research about white lions, but I didn't find anything, It's like my race doesn't exist, so maybe when I born, my parents... when they saw my color, they maybe thought that I was curse or something, and they abandoned me for that..."

"Rengar... please..." whispered Ahri

"They wanted my death... I shouldn't exist..." said Rengar

Ahri sat on Rengar chest and slapped him.
"Don't say such a thing! If you have join the league, that mean you have a reason to live, and if you still fighting, that mean you haven't given up on your dream..."
Ahri suddenly stopped, she bend her face, and tried to not cry
"I'm not sad because i'm rejecting the fox inside me, even if my body change I will be always the fox I was... It's just my dream will never come true."

"You finally realize it" declared Rengar

"Wait... you knew?" asked Ahri

"You reason to fight is for becoming human, but tell me, do you want to fight, after you become human?" asked Rengar

"Well... no." responded Ahri

"If you don't have one, then do you think the league will let go, one of the most popular champion in the league, just because his dream come true, and he don't want to fight anymore?" asked Rengar

Ahri didn't respond, and stay silent, realizing that her dream will never come true.

"I want my collection to be complete, and for that I need Kha'Zix's head, but when I finally got it... you saw what happened to his head earlier... I'm fighting for no reason, I will fight the rest of my life here. See, I don't have a reason to live here too, and I can't do anything about it." expressed Rengar

"Like me your dream will never come true, I realize it a long time ago, because my body wasn't changing, even if I was fighting every day, I don't change at all. I don't want a life like that, fighting every day for the rest of my life... sound great..." said Ahri

She slowly started to cry, she couldn't take anymore. Her dream, her life have been taken away by those summoner. She lie down on rengar chest and cried. Rengar hugged her, with his big arms, and slowly caressed her head with his right hand, trying to comfort her.
"You are perfect just the way you are." declared Rengar

Ahri raised her head and looked at Rengar.

"I imagine you without your nine tail, and your fox ears... It's true you will be beautiful, but something is missing, you will be like all humans. You will be too commun. Like you are now, you are special , we can't miss you, and plus you still beautiful even like that."

Ahri suddenly giggled
"You are a bad seducer." expressed Ahri

"I'm a hunter, not a seducer." said Rengar

"Me I'm a hunter and a seducer," declared Ahri

"You are a hunter?" asked Rengar

"Yeah, I hunt the love of man, a love hunter." responded Ahri

Rengar suddenly burst of laughed.
"A...a love... hunter... I heard everything, but that." said Rengar, continuing to laugh

Ahri was upset, she passed her hands under Rengar's armor and started to tickling him.

"Hey stop!" yelled Rengar

"I will stop if you excuse yourself." declared Ahri

"Fine, I'm sorry." expressed Rengar

"And..." continued Ahri

"Lo..." started Rengar

"What did you say?" asked Ahri

"Lo... hun..." repeats Rengar

"You know I can use my nine tails, for tickling too?" insisted Ahri

Rengar knowing that she was serious, and he didn't like tickling, he gave up.
"Love hunters are the best." said Rengar

Ahri suddenly stopped tickling him, and Rengar could finally breathe calmly.

"I always thought you were a brute, but you are really cute." said Ahri

Rengar blushed
"It's not my fault if all summoner want me to be like a big brute, and don't repeat this to everyone." said Rengar

"That you are ticklish?" asked Ahri
Rengar slowly nodded embarrassed about this weakness.
"In exchanged, I want something."

"Fine, tomorrow I will invited you to the restaurant." said Rengar

Ahri smiled, and passed her arms behind Rengar's neck.
"Thank you Rengar, I feel better now."

"I should be the one thanking you, I never have that kind of fun before." declared Rengar

"Why did you help me?" asked Ahri

"It's because..." started Rengar
He remained silent.

"Tell me, or I will do it again." said Ahri

"...I don't like when you are sad, I want you to be happy, because... I really like your smile, and... I really love you..." declared Rengar

" Do you want to know a little secret?" asked Ahri

"Sure." responded Rengar

"I didn't come here this night, because I was avoiding every men of the league, it just I was curious why you were the only men in the league who wasn't trying to seduce me, and that why I was really interested in you, because you were different. Sometime women are more interested in men who are hard to get." murmured Ahri

"If you want to know why, it's because all men are after you, and since I was always alone in my territory, I didn't know how to approached you,so I gave up." said Rengar

Ahri faced Rengar
"Then Rengar, will you become my new dream?" asked Ahri

"And you, will you become my reason to live?" asked Rengar

They looked at each other for a little time, and smiled together
"I will" said Rengar and Ahri together

Ahri kissed Rengar on his lips, sealing their promise, after a passionate kiss, Ahri slowly released his lips.
"Can we come here again?" asked Ahri

"Anytime you want it." responded Rengar

After some time, they decided to leave the summoner's rift. When they returned to the league, some champions were there. They were all surprised, when they saw Ahri and Rengar holding hand. Men champion were angry, and women champions were happy for them. Rengar blushed, and looked away, he wasn't habituate to be looked like that. Ahri smiled, hugged Rengar's arm and started to walked, forcing Rengar to follow her. When they left the room and closed the door. Ahri started to laughed and after a little time Rengar laughed too. Suddenly Ahri stopped laughing when see focus her gaze on the League's main door, Rengar stopped laughing too, and follow her gaze.

"Maybe one day, we will find way to leave the league." said Rengar

"If we arrive to leave the league, we'll you be by my side?" asked Ahri

"I will" responded Rengar

They returned to there room, when they arrived in front of Ahri's room, Ahri give to Rengar a goodnight kiss and she entered her room. At first Ahri was hoping that Rengar will passed the night with her, but too much champions were looking at them, so they decided that it will be for an another time,Rengar started to walked away with his heart still pounding, thinking about tomorrow.

I hope you enjoy, please review, it's really important to me to know what do you think of them. If you want to know why I do RengarXAhri, it's because of " A New Dawn", because they were together at the end. ( Leona was there too, but...Sorry Leona!) And they are my favorite character with Volibear and Sona(Should I do a VolibearXSona? Or more RengarXAhri?)